diff --git a/addons/account/data/account_data.xml b/addons/account/data/account_data.xml
index 5459f806eee..0072a949d89 100644
--- a/addons/account/data/account_data.xml
+++ b/addons/account/data/account_data.xml
@@ -155,7 +155,7 @@
             <field name="object">account.invoice</field>
         </record>
 
-        <!-- mail: subtypes -->
+        <!-- Account-related subtypes for messaging / Chatter -->
         <record id="mt_invoice_validated" model="mail.message.subtype">
             <field name="name">Validated</field>
             <field name="res_model">account.invoice</field>
diff --git a/addons/account_voucher/account_voucher_data.xml b/addons/account_voucher/account_voucher_data.xml
index fc008e479e9..7e11f625d9e 100644
--- a/addons/account_voucher/account_voucher_data.xml
+++ b/addons/account_voucher/account_voucher_data.xml
@@ -13,7 +13,7 @@
 <p>You can track customer payments easily and automate follow-ups. You get an overview of the discussion with your customers on each invoice for easier traceability. For advanced accounting features, you should install the "Accounting and Finance" module.</p>]]></field>
         </record>
 
-        <!-- mail: subtypes -->
+        <!-- Voucher-related subtypes for messaging / Chatter -->
         <record id="mt_voucher" model="mail.message.subtype">
             <field name="name">Status Change</field>
             <field name="res_model">account.voucher</field>
diff --git a/addons/crm/crm_lead_data.xml b/addons/crm/crm_lead_data.xml
index e2f1c307bfb..e7605c00a1c 100644
--- a/addons/crm/crm_lead_data.xml
+++ b/addons/crm/crm_lead_data.xml
@@ -154,56 +154,52 @@
             <field name="object_id" search="[('model','=','crm.lead')]" model="ir.model"/>
         </record>
 
+        <!-- CRM-related subtypes for messaging / Chatter -->
         <record id="mt_lead_convert_to_opportunity" model="mail.message.subtype">
             <field name="name">Convert to Opportunity</field>
             <field name="res_model">crm.lead</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_lead_stage" model="mail.message.subtype">
             <field name="name">Stage Changed</field>
             <field name="res_model">crm.lead</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_lead_lost" model="mail.message.subtype">
             <field name="name">Lost</field>
             <field name="res_model">crm.lead</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_lead_won" model="mail.message.subtype">
             <field name="name">Won</field>
             <field name="res_model">crm.lead</field>
         </record>
 
+        <!-- Salesteam-related subtypes for messaging / Chatter -->
         <record id="mt_salesteam_lead" model="mail.message.subtype">
-            <field name="name">Leads Created</field>
+            <field name="name">Lead Created</field>
             <field name="res_model">crm.case.section</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_salesteam_lead_opportunity" model="mail.message.subtype">
-            <field name="name">Leads to Opportunity</field>
+            <field name="name">Lead to Opportunity</field>
             <field name="res_model">crm.case.section</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_salesteam_stage" model="mail.message.subtype">
-            <field name="name">Leads Stage Changed</field>
+            <field name="name">Lead Stage Changed</field>
             <field name="res_model">crm.case.section</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_salesteam_lost" model="mail.message.subtype">
             <field name="name">Opportunity Lost</field>
             <field name="res_model">crm.case.section</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_salesteam_won" model="mail.message.subtype">
             <field name="name">Opportunity Won</field>
             <field name="res_model">crm.case.section</field>
         </record>
+
     </data>
 </openerp>
diff --git a/addons/event/event_data.xml b/addons/event/event_data.xml
index 47efca17d6d..490a2b869e7 100644
--- a/addons/event/event_data.xml
+++ b/addons/event/event_data.xml
@@ -12,9 +12,9 @@
             <field name="state">open</field>
         </record>
 
-        <!-- mail: event subtype -->
+        <!-- Event-related subtypes for messaging / Chatter -->
         <record id="event.mt_event_registration" model="mail.message.subtype">
-            <field name="name">New Registrations</field>
+            <field name="name">New Registration</field>
             <field name="res_model">event.event</field>
             <field name="default" eval="False"/>
         </record>
diff --git a/addons/hr_expense/hr_expense_data.xml b/addons/hr_expense/hr_expense_data.xml
index 01b839582e3..c5f1b99bb11 100644
--- a/addons/hr_expense/hr_expense_data.xml
+++ b/addons/hr_expense/hr_expense_data.xml
@@ -25,16 +25,17 @@
             <field name="default" eval="False"/>
         </record>
 
+        <!-- Expense-related subtypes for messaging / Chatter -->
         <record id="mt_expense_approved" model="mail.message.subtype">
             <field name="name">Approved</field>
             <field name="res_model">hr.expense.expense</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_expense_refused" model="mail.message.subtype">
             <field name="name">Refused</field>
             <field name="res_model">hr.expense.expense</field>
             <field name="default" eval="False"/>
         </record>
+
     </data>
 </openerp>
diff --git a/addons/hr_holidays/hr_holidays_data.xml b/addons/hr_holidays/hr_holidays_data.xml
index ad15f170e56..54240eeea0b 100644
--- a/addons/hr_holidays/hr_holidays_data.xml
+++ b/addons/hr_holidays/hr_holidays_data.xml
@@ -45,19 +45,17 @@
             <field name="color_name">brown</field>
         </record>
 
-        <!--subtype for leaves -->
+        <!-- Holidays-related subtypes for messaging / Chatter -->
         <record id="mt_approve" model="mail.message.subtype">
             <field name="name">To Approve</field>
             <field name="res_model">hr.holidays</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_approved" model="mail.message.subtype">
             <field name="name">Approved</field>
             <field name="res_model">hr.holidays</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_refused" model="mail.message.subtype">
             <field name="name">Refused</field>
             <field name="res_model">hr.holidays</field>
diff --git a/addons/hr_recruitment/hr_recruitment_data.xml b/addons/hr_recruitment/hr_recruitment_data.xml
index cb59d4ff9d7..a9bc7440276 100644
--- a/addons/hr_recruitment/hr_recruitment_data.xml
+++ b/addons/hr_recruitment/hr_recruitment_data.xml
@@ -461,7 +461,7 @@
         <field name="alias_user_id" ref="base.user_root"/>
     </record>
 
-    <!-- mail: subtypes -->
+    <!-- Job-related subtypes for messaging / Chatter -->
     <record id="mt_applicant_new" model="mail.message.subtype">
         <field name="name">New Applicant</field>
         <field name="res_model">hr.job</field>
@@ -481,6 +481,7 @@
         <field name="res_model">hr.job</field>
         <field name="default" eval="False"/>
     </record>
+    <!-- Applicant-related subtypes for messaging / Chatter -->
     <record id="mt_stage_changed" model="mail.message.subtype">
         <field name="name">Stage Changed</field>
         <field name="res_model">hr.applicant</field>
@@ -496,5 +497,6 @@
         <field name="res_model">hr.applicant</field>
         <field name="default" eval="False"/>
     </record>
+
 </data>
 </openerp>
diff --git a/addons/hr_timesheet_invoice/hr_timesheet_invoice_data.xml b/addons/hr_timesheet_invoice/hr_timesheet_invoice_data.xml
index a57f0c6078a..895329debfc 100644
--- a/addons/hr_timesheet_invoice/hr_timesheet_invoice_data.xml
+++ b/addons/hr_timesheet_invoice/hr_timesheet_invoice_data.xml
@@ -22,7 +22,7 @@
             <field name="factor">20.0</field>
         </record>
 
-        <!-- mail: subtypes -->
+        <!-- Analytic-account-related subtypes for messaging / Chatter -->
         <record id="mt_account_renew" model="mail.message.subtype">
             <field name="name">Contract to Renew</field>
             <field name="res_model">account.analytic.account</field>
@@ -35,6 +35,7 @@
             <field name="name">Contract Renewed</field>
             <field name="res_model">account.analytic.account</field>
         </record>
+        <!-- Salesteam-related subtypes for messaging / Chatter -->
         <record id="mt_salesteam_renew" model="mail.message.subtype">
             <field name="name">Contract to Renew</field>
             <field name="res_model">crm.case.section</field>
diff --git a/addons/mail/data/mail_data.xml b/addons/mail/data/mail_data.xml
index b095c54247f..f59ddd1c3ea 100644
--- a/addons/mail/data/mail_data.xml
+++ b/addons/mail/data/mail_data.xml
@@ -27,6 +27,7 @@
             <field name="priority">1000</field>
         </record>
 
+        <!-- Discussion subtype for messaging / Chatter -->
         <record id="mt_comment" model="mail.message.subtype">
             <field name="name">Discussions</field>
         </record>
diff --git a/addons/purchase/purchase_data.xml b/addons/purchase/purchase_data.xml
index 7a56e0dc95f..3be0587388f 100644
--- a/addons/purchase/purchase_data.xml
+++ b/addons/purchase/purchase_data.xml
@@ -48,17 +48,18 @@
             id="purchase_default_set"
             model="ir.values"
             name="set"/>
-        
+
+        <!-- Purchase-related subtypes for messaging / Chatter -->
         <record id="mt_rfq_confirmed" model="mail.message.subtype">
             <field name="name">RFQ Confirmed</field>
             <field name="res_model">purchase.order</field>
             <field name="default" eval="False"/>
         </record>
-        
         <record id="mt_rfq_approved" model="mail.message.subtype">
             <field name="name">RFQ Approved</field>
             <field name="res_model">purchase.order</field>
             <field name="default" eval="False"/>
         </record>
+
     </data>
 </openerp>
diff --git a/addons/sale/sale_data.xml b/addons/sale/sale_data.xml
index 7d03e227e7f..cfedc8ee850 100644
--- a/addons/sale/sale_data.xml
+++ b/addons/sale/sale_data.xml
@@ -44,27 +44,27 @@
 <p>If you need to manage your sales pipeline (leads, opportunities, phonecalls), the <i>CRM</i> application may be useful. Use the Settings menu to install it.</p>]]></field>
         </record>
         
-        <!-- Subtype: sale.order -->
+        <!-- Sale-related subtypes for messaging / Chatter -->
         <record id="mt_quotation_sent" model="mail.message.subtype">
             <field name="name">Quotation sent</field>
             <field name="res_model">sale.order</field>
         </record>
-
         <record id="mt_order_confirmed" model="mail.message.subtype">
             <field name="name">Sale Order Confirmed</field>
             <field name="res_model">sale.order</field>
         </record>
 
+        <!-- Salesteam-related subtypes for messaging / Chatter -->
         <record id="mt_salesteam_sent" model="mail.message.subtype">
             <field name="name">Quotation sent</field>
             <field name="res_model">crm.case.section</field>
             <field name="default" eval="False"/>
         </record>
-
         <record id="mt_salesteam_confirmed" model="mail.message.subtype">
             <field name="name">Sale Order Confirmed</field>
             <field name="res_model">crm.case.section</field>
             <field name="default" eval="False"/>
         </record>
+
     </data>
 </openerp>