Real-time Attribution
I was working on a blog post tonight and wanted to attribute a person as the source. Normally, I would just link their name to their site/blog if they had one, which would then alert them by email if they had a Google search alert on their name or URL, or it would show up as an incoming link in their WordPress admin. In the age of real-time (albeit still asynchronous), it would be great if I could have chosen to link to their @username on Twitter, and that would show up on their @mentions view.