It was said in a previous "diary" entry that OSM users are not a major issue "because nobody will actually see a user page for a user that doesn't do anything unless they actually go hunting for it for some reason" (from here).
But this is an example of spam user : https://www.openstreetmap.org/user/Voyancegratuiteimmediate
which is referenced multiple times from Facebook or Twitter (e.g. https://twitter.com/DabiaRamani)
The aim is probably to increase G. ranking. The same site is referenced in dozen different sites with the same kind of weakness. If it's not harming OSM, this miethod is artificially increasing the amount of registred users and will probably increase in the future if we do nothing.