Twitter have announced "Expanded tweets":
http://blog.twitter.com/2012/06/experience-more-with-expanded-tweets.html
which will feature summaries of linked articles from partners such as
newspaper websites.
Is anyone talking to them about doing so for Wikipedia articles?
(Obviously, we wouldn't pay them to do so)
--
Andy Mabbett
@pigsonthewing
http://pigsonthewing.org.uk