More often than not, when a company files a patent, it's simply to defend the idea. There's a good chance Sony has no intention of ever actually implementing this. They've always been very good about their ads so I don't really understand why they'd jump to this.
I'd be fine with it if it was coupled with free games. For example, they already offer hour-long "demos" of full games to PS+ members. I'd endure commercials and ads if I could play a full game for free that way. Or something like that. I can see it working, but they'd have to be very careful about it because it sounds pretty distracting and people wouldn't stand for it unless there was a good reason to.
And the worst part is, all those ads show up whether you're a Gold member or a Silver member, right? So even if I pay them $60/year (which I no longer do and probably never will again), I'm still subjected to the same number of ads. I guess that's akin to paying for cable/satellite and still having to watch the ads but at least I get more TV content than ads when I watch something which is not my experience with the overcrowded dashboard. Sony's ads, on the other hand, are so classy. You only see 'em when you're resting on the PS Store icon and the small, scrolling marquee in the corner can be toggled on and off. The ads aren't intrusive at all.