[genwin]

But Microsoft largely escaped the DOJ antitrust case because of competition with Apple. (MS invested in Apple to retain a competitor.)

People aren't really forced to use craigslist. That the vast majority of people choose to search CL isn't good enough. Another company could spend whatever it takes to get people to search their classifieds instead. As long as CL can't or doesn't block that (in contrast to stuff MS was doing that started the DOJ case against them), the competition is viable.