Taken from Andrew's blog "Dolphin U - Alpha 6" post.
Hashtags
Data needs categorisation. Dolphin U now features metadata format called "Hashtags". They're non-hierarchical keywords that can be created just by adding # (hash) symbol before any word within a post. Simple as that. Once content is posted hashtags turn into links that show all posts or other data with those hashtags. Unlike with the "old-fashioned" meta-tags there's no need for a separate input form. Keywords are created while typing the main content body. This concept is particularly popular with Twitter, but is rapidly becoming popular on Facebook and other social networks. Uninterrupted creative flow FTW!
This is a great improvement.
Are we going to see this in the "posting" a comment to these post?
Currently you cannot comment and include an additional hashtag.