It's not a LibraryThing or GoodReads; it's meant for libraries that are institutions. That said, I don't think there is anything stopping an individual person signing up and entering their collection, but there would be no point in paying the fees unless you had (say) a unique scholarly collection and wanted to lend books to other libraries - and if so, in the long run you'd likely be better off seeing if a library wanted to acquire your collection.