Twitter updates its terms of service, making them nicers to users, imho. The gain rights to distribute your content, but they state very clearly that the content belongs to you, not to them. They retain the rights to add advertising, cut on spam, and make the content available to third parties via their API.

You can read more info at this blog entry: http://blog.twitter.com/2009/09/twitters-new-terms-of-service.html. You can also read the full TOS document at: http://twitter.com/tos.

How did I realize? Thanks to a nice email send to all Twitter users by Biz Stone, Twitter co-founder:

We'd like to let you know about our new Terms of Service. As Twitter
has evolved, we've gained a better understanding of how folks use the
service. As a result, we've updated the Terms and we're notifying
account holders.

We've posted a brief overview on our company blog and you can read the
Terms of Service online. If you haven't been by in a while, we invite
you to visit Twitter to see what else is new.

Overview: http://blog.twitter.com
Terms: http://www.twitter.com/tos
Twitter: http://www.twitter.com

These updates complement the spirit of Twitter. If the nature of our
service changes, we'll revisit the Terms as necessary. Comments are
welcome, please find the "feedback" link on the Terms of Service page.

Thanks,
Biz Stone, Co-founder
Twitter, Inc.