When you post an article on Universal Hub, you get lists of neighborhoods and topics so you can select which categories the article will appear in. Very handy.
But what if you want to post about something your slug of a site editor has yet to create a category for? Like, oh, Leominster? Or what if the categories aren't specific enough? Like, say, you want to post about something on the Orange Line, and the best you can find is "The T"?
Free tagging to the rescue!
From now on, when you post an article, you'll get a text box in which you can enter all the keywords you think apply to your article. Yes, just like Flickr. So say you want to post about some crazy person screaming at you on the Orange Line? OK, bad example, that would never happen, but work with me. Enter something like this in the Free Tagging box:
Orange Line, crazy people, screaming
When you post that article, voila, you've just created three new categories (unless they already exist, in which case, they'll be added to the categories). You can see all the "free" categories on the Categories page. As with other categories, each "free" category has its own RSS feed, so you'll be able to track all the postings about crazy people or whatever.