Earlier quoted context omitted.
The magic recipe that keeps people coming back is that Craigslist has a large network. I would be willing to bet a large amount of money that adding a map to search results and letting me put an upper limit on the number of bedrooms I'm looking for would not make people less likely to use Craigslist.
Their magic recipe is that an amazing amount of non-technical people have figured out how to work with the site. The Dutch version of Craigslist (Marktplaats, owned by eBay) is in a similar predicament. They have a very sucky UI and have experimented with new and improved versions, but every improvement was quickly reverted after large drops in engagement. It's almost surreal to look at their site ( http://marktplaat…
http://amsterdam.craigslist.org/apa/
But if I might inject an opposing data point, nobody seems to use the Brazilian version of Craigslist. Check out Sao Paulo:
http://saopaulo.craigslist.org/apa/
Can you believe that there are just 5 apartment listings for a metropolitan area of 19.9 million!
It's incomprehensible to me why Craigslist doesn't work there, especially since all the alternatives involve paying some middleman for listing. The same goes for job sites and "things for sale" sites as well. Brazilians prefer to use some scammy-looking sites loaded with graphics and eye candy and often charging a fee, rather than the vanilla Craigslist.
I'm going to venture a guess that this has much more to do with trust (Brazilians want to feel that someone has vetted the data) than with good/bad UI or web design.