Tomorrow at 8AM Pacific, Twitter will do something that will befuddle many end-users. 

http://blog.twitter.com/2010/08/twitter-applications-and-oauth.html  

I can't think of a precedent, a time when a platform vendor deliberately broke so much application software. It's possible that it's happened and I don't remember, but I find it hard to believe that I would not have heard of it. So much app breakage would surely make a loud sound!  

Twitter says it will mean improved security.  

I think it means for sure fewer user-hours spent with apps not developed by Twitter, Inc. 

Some of my apps will die tomorrow. For example, FriendsOfDave and dwcodeupdates. It probably won't be worth it to convert these little apps to use OAuth. It will impact very few people, mostly me. (FOD is like a quick aggregator for people whose updates I never want to miss. Codeupdates helps me confirm that updates made it through the OPML Editor's code management system. Neither are mission-critical, just nice-to-have.)  

I'm sure tomorrow I'll learn of other Twitter-related apps that will not be updated. If you learn of any feel free to post a comment here.