Mobile carriers blocking numbers -- or entire ranges of numbers, for that matter -- isn't entirely unheard of; 900 and 976 numbers are frequently locked down, for example. Blocking legitimate services running on standard toll numbers is another matter entirely, though, and that seems to be what's happening here. FreeConference, which offers, well... free teleconferencing services by dialing into standard long distance numbers (as its name suggests) has had several of its lines locked out by AT&T, Sprint, and Qwest starting this month. At issue is the reason behind the sudden could shoulder, a reason disputed by FreeConference and the carriers. While FreeConference claims that the carriers are simply forcing users into using their own (more expensive) conferencing services, a more plausible (and slightly less blatantly illegal) explanation is that carriers are getting billed through the nose for termination fees stemming from FreeConference's non-toll-free numbers. Either way, it's uncool, and we're thinking it might be a good enough reason for frequent users to ultimately end up switching carriers.
[Thanks to everyone who sent this in]