For many old-school video game players, you may have noticed on some sites games such as Sonic titles on the genesis and Mario titles have been become "un-downloadable" meaning, they still have it up there, but due to the ESA rule it cannot be downloaded.
This goes for a lot of romsites, and there are a few sites that still havent been affected by the ESA thing, but you may want to look out and download what you want now, rather than waiting. Doesn't seem that much of a deal because of the wii's virtual console and xbox live and psn but for people not wanting games of it or games not on them it may become difficult.