Update: Stocktwits CEO Howard Lindzon claims that Twitter ripped off their idea.
Twitter has just added support for another element on their platform.
They already have support for mentions and hashtags. The latest supported element is stock and company symbols.
Essentially, stock symbols are now linked to their search results if they are posted in this format $GE.
Here is an example tweet from the company itself:
— Twitter (@twitter) July 31, 2012
Update: Looks like this is not working on embedded tweets right now.