Compare the coverage of Quora versus StackExchange, for example. There was a period when there were two Quora articles per day on TC. StackExchange is lucky to be mentioned once every few months, and even then it's usually only brought up as a comparison to "Quora and other Q&A sites".
What good does it do for a startup to be featured on TC? I suspect it may have to do with getting funding if you are doing a round, but is that it? I would assume that most startups don't derive many paying/staying customers from a TC post, unless the startup itself is narrowly targeted at entrepreneurs/other startups.
Quora made it to regular press, dailies, TV tech news, etc. but I've not personally seen SE in those media.
(I don't think that the two sites should be directly compared, btw -- I was just noting that they had been whenever SE was mentioned.)