The service is live both on the Web and in a new app for Android devices running on 4.0 (Ice Cream Sandwich) and above.
Keep gives Google users a central place to store the information they collect from its various services. People are doing this already in Google Docs -- keeping to-do lists, recipes, and other short snippets of text on individual documents.
Here's how the company put it in a blog post:
"With Keep you can quickly jot ideas down when you think of them and even include checklists and photos to keep track of what's important to you. Your notes are safely stored in Google Drive and synced to all your devices so you can always have them at hand.
If it's more convenient to speak than to type, that's fine: Keep transcribes voice memos for you automatically. Also, there's a search function to quickly find specific notes. And when you're finished with a note, you can archive or delete it."
The service will feel familiar to users of Evernote, the note-taking service and self-described "external brain" that has more than 45 million registered users. (Business Insider wasted no time in labeling Keep an "Evernote killer.") Evernote also focuses on making it easy to create and search notes; it has brought its service to an impressive number of platforms.
But Keep has an additional, more Google-y forebear: Google Notebook, which launched in 2006 as a way to collect online research and other notes into a single place. (For a time, Google search results were accompanied by a "Note this" link that would send the search result into Notebook.) The product was in development from 2006 to 2009, but only disappeared completely from Google in June 2012. Existing notebooks were imported into Google Docs.
Given Google's ambivalent history with note-taking services, and the recent, high-profile sunsetting of Google Reader, users may be reluctant to record all their information in Keep.
But there is no end of ways Google could integrate Keep into its products, and by making it easy to -- for example -- send over Google Maps directions or snippets from Gmail, the product could build a loyal audience. It also will be interesting to see whether Keep fits into Babble, the rumored integrated communications platform that Google is said to be building. Lots of notable communication takes place in Chat windows, and easy Keep integration could help give it a lift.
Here's a video Google put together to show off Keep: