Last.fm is hiring Toby Padilla as VP of desktop and client software and, with it, the developer is closing his Musicmobs website after four years. Musicmobs had operated in Last.fm’s social music space right from the start, using a client application for iTunes, Mobster, to let users trade playlists and sync listening stats as well as get recommendations on new tunes.

But, in a note that replaces the Musicmobs front page today, Padilla wrote rising costs and growing competition had last year forced him to seek a buyout. Discussions with Last.fm resumed after its May $280 million sale to CBS (NYSE: CBS) and have resulted in him being brought on board from Seattle to help ”take the Last.fm desktop player to the next level”.

The two services are so complementary, the pair are calling themselves the “social music dream team” - much of Padilla’s work will now inform Last.fm’s (via Last.fm blog). Unclear how Toby will fit in with his indie-kid colleagues round Shoreditch way, though - his musical preference is hard rock like Pantera, Megadeth and Europe