Google Docs' days are numbered. Google has pitched Google Drive as a replacement to Google Docs since its release in April. What I, along with many users, didn't realize is that Google will be killing off Docs and transitioning all users to Drive. Drive is currently still opt-in, but it looks like soon users will be opted-in automatically as their Docs account is upgraded to a Drive account.
In fact, Google has started to warn users of just this fact. It seems as though this transition is coming sooner rather than later, and Google's transition documentation supports that saying that "we expect to finish the transition from the Google Documents List to Google Drive by late summer (2012)."
This transition will occur in three phases. Currently, users are in phase one, or the "opt-in phase." From there, users will be allowed to opt-out for a little while longer if they would like more time to transition. Once users are moved onto phase three, everyone will have a Google Drive and Google Docs will no longer exist.
This isn't exactly a bad thing. Drive is a good replacement and has the same capabilities as Docs and even comes with more storage. Unlike the controversial Gmail upgrade, one could argue that Drive is the next logical step for the Docs app to make. I doubt many people will complain over the forced upgrade as much as they did over the Gmail one.