It hasnt always been clear which sites have been affected. Mashable reached out some of the most popular social, email, banking and commerce sites on the web. We've rounded up their responses below.
Comprehensive list, with some big names on in: Facebook, Google, Yahoo, Dropbox, etc. Most of them have already been patched, but if you use any of those services (and chances are, you do), you should take a minute to change your password as soon as possible.
Also, it’s a good idea to enable 2-step verification for those sites that support it.