I urge people to think twice before publicizing their UDIDs. Many apps have very serious shortcomings in the way they deal with UDIDs, which means that an attacker armed with your UDID could potentially access accounts and personal information.
See here for some recent examples, looking just at a single industry (social gaming networks):
http://corte.si/posts/security/udid-must-die/index.html
I can tell you with absolute confidence that this is just the tip of the iceberg.
