Sorry for take so long to reply. Indeed the list is a little bit empty, but it's because we are working hard to release new version of AMS. :)
Why you say it doesn't scale? Performance?
Which version of AMS are you using it?
The first thing that come to my mind is compost cache. The Thing attributes would be cached but not the Liked flag.
There are some ways of doing it, you may find it on google :)
But I will try to address this kind of situation with a easier solution on the next version of AMS.
Best,