So the story here is ... Techcrunch published a story about an acquisition that turned out to have no basis in fact. TMZ seems like a more reliable source for gossip.
TMZ isn't a good example. When it comes to breaking celebrity news, they actually exercise a great deal of journalistic integrity and restraint. They're very reliable and very well-sourced.
TechCrunch reported that Google and Yelp were in talks for an acquisition. As far as I know, that is true and TechCrunch broke the story with original reporting.
Then TechCrunch reported that Yelp walked away and talks broke down. As far as I know, that is also true and again they broke the story with original reporting.
Remaining agnostic to your claim about TechCrunch, how does this situation support the argument that they are not reliable?