I had an idea that since some guild are blacklisted or you just don't like them very much that it would be good to have a ignore addon that would look through the guild rooster every now and then and ignore all that they find... And if you see a player that the addon ignored that left the guild it would automaticly unignore him/her. Would ofcourse be used in cooperation with an infinite ignore addon.
What do you think ? I can't code for the life of me but if someone would be interested or know of a addon with this functionality let me know :P
I talk out of experience when i say that having piece of mind, ignoring though reading (read, not caring), is always better then to programmatically exclude the 'hostile' messages. When in such state of mind, one doesnt have to think about incignificant matters like this anymore. Furthermore; If you really want a scripted alternative, there are AddOns that make each message appear only once ('STFU' is one). Peace and serenity.
Well, uh, you can only pull up guild roster for the guild you're in, so your idea's kinda broken there :) You could of course ignore anyone you come across that has a blacklisted guild in their info. I have to agree with Indie tho, there's only one thing I complete fliter out, /spit, and I don't /ignore the person that does it, just suppress that one line of text.