After googling I found that Nemein is a web services development company, I did not know that. So other than the fact that they developed part of maemo.org, why would they host/sponsor maemo.org ?

And I assume you mean Nemo, since memo.org doesn't seem to be of much use.
I know it is some kind of alternative OS for N9xx, based of MeeGo and Mer project, but I have no idea who are active in development and how big that community is.