What to do on a release

Fix the new version number based on the rule above and update /VERSION.
Update version numbers in source code(/twittering-mode.el).
Add new version number to /NEWS and describe updates.
Update version numbers on web pages(/doc/web/index.text).
Change the version number in /VERSION to next (expected) version number.
Make a tag v<VERSION>
Upload new source files to souceforge.net
Publish web pages(cd doc/web; make upload).
Release announce on MLs.
Release announce on freshmeat.net.
Release announce on Twitter.