Ed Foster, on the difference between a bad sneakwrap license and DRM that revokes your rights without any "ask" at all:

So what's the connection between DRM and sneakwrap terms? The common thread is that with both, customers don't really know what they're buying when they put their money down, or at least not without reading through multiple layers of fine print. And they might as well not bother to do that, because the deal can be changed retroactively by the seller as you go along. Hey, you have been granted certain rights, up until the time we decide to take them away from you, at which point you have no rights.

For the vendors, of course, DRM also means never having to go before to judge to argue that their unconscionable EULA terms should be enforced, because the DRM is judge, jury and courtroom, all rolled into one.