No-one knows what this means, but there is plenty of speculation that the NSA or some other agency might have put the developers under pressure. Is TrueCrypt the new Lavabit?
Discussions on reddit:
http://www.reddit.com/r/netsec/comments/26pz9b/truecrypt_development_has_ended_052814/
http://www.reddit.com/r/sysadmin/comments/26pxol/truecrypt_is_dead/
http://www.reddit.com/r/linux/comments/26qe9f/truecrypt_is_not_secure_official_sourceforge_page/
Discussions on Hacker News: