I think Google, Facebook, and especially Yahoo did significant damage to their reputations and brands through how they have disposed of products both for consumers and developers. It is really hard to take anything they put out seriously until that product has been around a long time and is clearly being supported, used, and polished.
Google and Facebook are still large, strong, and growing, but what Yahoo did to all of the companies it acquired really fucked both their investors and customers. One wonders if Google and Facebook will wander down that path when their growth stalls out.