It used to be that the macros would buy the micros and just close them down so they could get the rights to one of their products. Then they would change it to make more money...and ruin it. Now they are trying to turn out their own pseudo micros. Usually they are failures though. Blue Moon was successful but most of them don't last very long. Pete's was another one that was sort of successful. That has been made by Gambrinus for quite some time now. They did try investing in some of the breweries but they don't do that quite as much anymore since the big microbrew boom surge slowed it's pace a bit.
Oh, and about Red Hook, Busch owns about 1/3rd of that company now too. Has for a while actually. I really like the Smuttynose line of beers. Their IPA and their Robust Porter are great. Their big beer series is really good too. Their lager is their weakest I think but still not too bad for a northeast lager (for some reason we can't seem to make the great ones up this way). I'm more of an ale guy anyways.