Google Bookmarks

Google just introduced version 4 of Google Toolbar for Internet Explorer including support for centralized bookmark tagging and notation from multiple computers. The new feature allows any toolbar user with a Google account to store bookmarks within their Google search history for synchronization and editing. Google bookmarks can also be added and edited via a web interface.

You can add a new Google bookmark anywhere on the web when logged in by passing Google a few Uniform Resource Locator (URL)-encoded values.
http://www.google.com/bookmarks/mark
title — the title of the bookmark
bkmk — the bookmark URL
labels — comma separated labels or tags
annotation — A note or description about the bookmark
s — 22 character user token
To edit a bookmark just resubmit the original URL with the new values. You should receive a response including a
star graphic if you are successful.
It should be possible for third-party applications to use Google’s bookmark storage system once you obtain the appropriate token.