But I do know that one of the versions I've used in the past couple of years (probably Outloook 98 or Outlook 97) had such a flaky "junk email" feature that I stopped bothering to use it. When my junk senders list got to a certain size, it would start automatically junking (moving to the deleted folder) Email from some people it apparently thought was in the list but who actually weren't there at all.

Very annoying when it was Email from coworkers asking relatively important questions or sending fairly important information to me.

All I really used it for was either junk senders, or "from mailing list" rules. Did a decent job of sending local user group Email into a user group folder - but the oddities got to be too much.