Google pulled this off with XMPP by having their Google Groups bridge be horribly maintained, feature incomplete, and randomly go down for days at a time. Most of the people on XMPP were on Google Groups so to them it just looked like the few people who actually hosted their own XMPP servers randomly went offline. It got to the point where people who used XMPP would have to create an account on Google Groups in order to reliably be able to talk to their friends. Google Groups users eventually came to the conclusion that it was XMPP that was unreliable.