I said this a few days ago, but I still feel like Sony is taking the "wait and see" approach with this all. They came out first and got people going with all the official coming out announcement of Next-Gen, but they didn't really need to do anything until E3, They knew it was only a matter of time before MS came out with their counter and would start mouthing off on why they're better/different.
At this point, Sony now has 3 weeks to prepare their E3 presentation, and they have the blunders of MS to build on. Even if they announce some of the same things like blocking used games, at least now they can come out and say it in their own language in an attempt to persuade gamers as to why its necessary or why its a good thing. Although I highly doubt that they will. The thing about MS is that they were willing to take risks that Sony and Nintendo wouldn't have because MS wanted to shake things up to give themselves a fighting chance and a lot of it seemed to work in their favor, like online communities and achievements. I think if blocking used games works out for MS in the long run, Sony will definitely try to adopt it then, but I don't see them doing it or talking about it now.