From an interview with one of my personal heroes:
"A lot of people obsessed with venture capital see Metafilter as a lifestyle business, but in my mind, it’s a mature business. It works really well and yet nobody aspires to do something like this and I don’t know why. Nobody celebrates just simple businesses that work."
I do, Matt! It's precisely what inspired our work on Domainr, which has essentially been profitable since the month we launched it.

The work Matt and PB have done with Metafilter and Fuelly, what Craig & co have done with Craigslist, Jason & co at 37signals, Buzz with PodWorks back in the day, Marco with Instapaper, the list goes on... is for me some of the most inspiring on the web. It's often DIY/homebrew/bootstrapped, always insanely useful, and ideally profitable.