The tweet contains the post title, a link to the question, and a hashtag based on the most popular tag on the question.
The accounts, and therefore the questions, would get better exposure if there was an additional site specific hashtag. For example, more people would see the @StackWordpress tweets if they also included the #WordPress hashtag, which would probably lead to community growth.
This wouldn't make sense for all sites (eg, I doubt SO would benefit from it), but I think that many (most?) of the the 2.0 sites benefit from this.
So, I am requesting that site communities get to
- vote (via their Metas) on whether they want a specific hashtag
- vote for what that hashtag should be