Check out my post on the Dailymile blog here. I've talked about dailymile before. I cannot express how much motivation and inspiration can be derived from the dailymile community. I had heard it said that Facebook leads one dislike people they've known for years, while Twitter makes one like people they've never met. I'd say dailymile is more like twitter in the sense that you end up with lots of friends there you've never met, but more like facebook in layout and format. It takes the best of both and integrates them with a workout log, mapping, and Garmin gps and Nike+ sync capability. If Facebook and twitter are social networks, I guess dailymile could be legitimately called a Social Fitness Journal.
The power of this isn't obvious until you dig into it, log some workouts, and give it enough time (it usually doesn't take long) for people to come out of the woodwork to offer words of respect and encouragement, no matter what your fitness level or performance. Indeed, dailymile is so good at inspiring this kind of interaction, that the benefits can go far beyond just keeping your on tack for your fitness goals. That's really what the "How We Succeed" series on the dailymile blog is all about.
Have a look, and whether you just want to walk more regularly, train for an Ironman triathlon or marathon, or just stay committed to your boot camp class, I think you'll find more than enough encouragement at dailymile--and a fair share of entertainment as well... Not to mention a lot of new online friends.