Ask HN: Are there any legal issues with using Twitter style at/hash Tags?

I'm working on a project and I wanted to use Twitter style inline @ and # tags and I was wondering is there any legal implications to that. As in has Twitter patented that? Is it even patentable?

As a side question, what do you guys think about inline tagging/referring. Is that good UX?

Thanks,

Drew

I think that hash tags are a great way to sort through information on a website (Especially if you can do some dual hashtag where you could have #Topic1 #Topic2, and it will return queries that only have both).

Not patented, they started in IRC channels.