Contrary to what you may expect, self promotional updates -- especially in the form of links to the thing you worked on -- are among the highest valued on Twitter, beaten only by questions at #1 and information sharing at #2. 
The old-fashioned "what are you doing now" update is the 3rd most disliked status. "Eating a sandwich" is oversharing.
One of the common suggestions of your SEO company is to get involved with communication on social networks, especially to seek out questions related to your product or service and then try to answer those questions as best as possible.
Twitter users self-reported that they're more likely to buy from businesses that answer their questions.
The second most used language on Twitter is Japanese.
Twitter is a US phenomenon first: over 107 million accounts are from US users, three times as many as runner up Brazil.
 Who Gives A Tweet? Evaluating Microblog Content Value [^]
 Twitter's Loaded Questions: How people ask and answer questions on Twitter [^]
 English expression stabilizes below 40% [^]
 Brazil becomes 2nd country on Twitter, Japan 3rd [^