These are my thought on the many efforts I see here to replace Craigslist.
Craigslist is massive and serves the local ad needs of many nearly-computer-literate people very well (wikipedia says it has the 33rd highest traffic in the world). It's html-from-1995 look works perfect and could work for a 1000 years.
Craigslist also doesn't make that much money relative to the traffic it has. It's run almost as a charity (28 staff people).
This is frustrating to potential entrepreneurs because when they get an idea for monetizing a need served by Craigslist, they realize that there's no money to be made because craigslist already fully meets the perceived need in a free and advertising-free fashion.
I'd say entrepreneurs probably need to not target the least-common-denominator, least-cash-on-hand group that is craigslist's vast customer base but rather target more well-healed subgroups (the only way to make money from craiglist customers is to educate them there's a need they don't yet know about - but when a large portion also don't have the extra money to pay for that need, the effort may be in vain).
So... just think, all the web's "disruptions" are about small outfits killing larger one with more efficiency, higher volume and lower margins. In this ideal, the margins start to go towards zero, don't they? What then? Craiglist is one answer but its not an answer that generates jobs, economic activity or wealth.
You might take notice that the number of people depending on craiglist has to do with the declining median incomes and lack of higher-paying, higher-skilled jobs which characterized the US economy even before the recession. You know the wikipedia page shows Craig Newmark standing with a hammer? How's that for disruption!
The new economy is supposed to create new needs, new jobs and new income. Has it done so in enough volume to sustain itself? What's your answer here?