Craigslist: mess or not, it's successful

[charmian]

I don't buy very many things online (most of the things I buy are perishable), so I've never used Craigslist; therefore, I cannot evaluate the thesis of the article re: the mess of Craiglist design very well. However, if the design and other things are so bad, just why is it that Craigslist continues to dominate the market? Is it only that they're 100% free (except for certain listings in certain areas)? However, I'm sure that other companies are trying the freebie approach as well (after all, look at twitter and all the other companies who seem to have no idea how they'll make money). Also, how is it that Craigslist is so successful with "backward" tech?