Even if you don't use Google+, you've probably entered a bunch of information into your Google profile from various places. Now you can manage it all in one spot in Google's AboutMe section.
The new page, which lives at aboutme.google.com, will show you all the information Google has that might show up in other Google services. Things like Google Drive, Photos, and Gmail all pull from the same profile to some degree or another, so this is a chance to manage it all. Despite having a similar name to online business card site About.Me, this doesn't seem to be a landing page for other people to see your profile. Just a handy settings page for you.