Editing Mail/Threading/Comparative (section)

== Gmail (Web app) ==
[[File:Gmail.jpg|alt=Gmail Threading|thumb|Gmail Threading]]
Gmail's threading stacks conversation messages with the newest unread message on top and the last two emails of a thread, prioritizing usability over precise message hierarchy and '''intentionally''' allowing users to expand the rest of the messages.

Gmail groups emails if each message meets the following criteria:

* The same recipients, senders, or subjects as previous emails.
* A reference header with the identical IDs as an earlier message.
* Sent within one week of an earlier message.

Gmail will break an email thread if the subject line changes or the email chain grows beyond 100 emails.

Asking myself, is there enough context for the user? '''Context from intermediate messages can be lost''', potentially leading to misunderstandings or incomplete information. The condensed view might not provide enough information for users to decide whether to open a thread or not.

Also the system could automatically groups messages that are nor supposed to be grouped.