Yes, Microsoft does have such a thing.
KB894199: Description of Software Update Services and Windows Server Update Services changes in content for 2012 lists everything that's been made available via Windows/Microsoft Update all year long. The newest updates are near the top. At the bottom of the page are links to previous years' articles going back to 2005. Of particular note: This article number always points to the current year, with previous years being archived into different KB articles, so you don't have to search for a new KB article every year.
There's also the Microsoft Update Catalog, where you can search for and download the published updates. I've always found it a bit... unusual, and difficult to use if I didn't have a KB article number.
Finally, a non-Microsoft source: kbupdate.info. It shows you lists of all KB articles organized by their last modification date. This also means that there's often relatively minor changes to older KB articles that cause them to pop up in newer lists. This lists all KB articles, so it will list security & non-security updates, hotfixes, informative articles, and fast-publish articles.