I went on to read the article written by Etienne Wenger regarding "Communities of Practice." Is was quite informative and very well written. I was interested as I read through it on how these "communities" form within organizations organically and many times without the "members" even realizing they have formed it. Looking back, I myself have been a member of many communities of practice never once realizing that I was.
Next I read the piece about Building Online Communities posted on the O'Reilly Network. It was quite informative and had some great information about why your community should have a reason to exist and how users draw other users. It goes on to say about how your community will develop it's leaders and trouble makers. Over all it was a nice piece and I added it to my personal Online Community Manager resources list.
So after going over all the information I believe that the definition of an online community is a gathering of people that band together (through whichever form of online media they choose whether it be a blog, wiki, forum or whatever) for a common goal or reason. For me personally I Play MMORPG's (massive multi-player online role playing games) which is a gaming online community. It uses many different online forms of online communities including the game it's self, online forums, guild websites, and I also have started my own personal blog where I give advise on how to be a MMORPG Guild Master.
Well that's my two-cents! I'm off to look up some classmates blogs and perhaps drop a comment or 2 :)