Don Roberts writes: : I am using Thunderbird, Karl. I noticed you used a new subject line but : it appeared in the thread for "PF exhibit of 9-20-08". I assumed that : you were hitting reply and then changing the subject heading. That : doesn't take it out of the thread. Am I wrong in my assumption? threads - that explains it.. Gmail and Tbird and many other mail programs handle threads in funny ways. Gmails buggy threading system has led to a lot of lost hair, but Thunderbird is something i'm not that familiar with, though most pages suggest threads are arranged based on subject line http://forums.mozillazine.org/viewtopic.php?t=303095 Q:"How does TBird handle threads? Looks like it only looks at the subject line and arranges it based on date. And does not look at messageID of the email. Is this true? " A:"It does both. " (followed by instructions to change things) <http://www.st-andrews.ac.uk/staff/itsupport/Email/Thunderbird/Thunderbirdh intsandtips/> "Message threads Another way of grouping messages together by subject is to click the "Thread" icon which is the leftmost column heading - it looks like a speech-balloon. If you click this, all the messages belonging to the same thread (ie with the same Subject line) will be grouped together" It seems some thread handling is done by subject line, some by message ID info - and each mail program has its own method of handling such things, and sometimes it works ;) The way I run mail is with folders. I set a few rules and incoming mail pops into those folders based on date. I do not use an 'address book' as in the unlikely chance I get hit with some nasty mailer virus, I'd rather my friends don't get bombed with whatever hit me, so rather than remembering an email address I hit reply. so, when I want to email someone/a group I hit reply, change the subject line and off it goes. Of course, how I set up my incoming mail and how it is received is my choice. Sending mail has commonly been done by hitting reply, typing the address manually or using an address book threading mail or linear mail arrangement seem in the hands of the recipient and their mail program but I'll try to change my habits if this makes things easier do others have problems with the way their mail is handled?