Version:            (using KDE 4.2.0)
OS:                Linux
Installed from:    SuSE RPMs

Email-filters work by detecting certain things in the email user receives. Kmail supports filters that are based on certain criteria. Like subject-line, sender etc. If user wants to create a filter, he needs to define the common things the filter will monitor for. In some cases finding this commonality in the emails could be quite hard.

What I would like to see is a system where the users could select a bunch of emails that he would like to see filtered, and he could tell Kmail to search for a common nominator in those mails, and create a filter based on it.

For example, user might receive a bunch of emails that he would like to see filtered. But those emails have different senders, and the subject-line is not standard. User could then select all those emails and tell Kmail to search for commonalities. Kmail could then tell the user that "all these emails contain phrase "tulip-season", would you like to create a filter based on this criteria?".

The system would be smart enough to not suggest singular words (like, "all these messages contain the word "the", create a filter based on this criteria?"). Rather, it could look for combination of words or otherwise uncommon words (like, Hyperbolicsyllabicsesquedalymistic).