The HL3 memes don't even seem fair to use anymore. I don't even want to un-seriously make joke fun of them at this point. They are just genuinely doing so much for the community.
Particularly when you can easily disable them. No other game client I know of offers that.
On the other hand, I don't classify what Steam is doing as advertising. When I open the Steam store, it's because I want to see the games it has on sale. It's not advertising, it's the exact information I asked for. It would have been advertising had it kept spamming me with game deals while I'm watching a film or something.