[gnaffle]

Both Asterisk and FreeSWITCH, both open source IP PBX projects, have conference bridges that support noise cancelling and speaker detection, and I think several conferencing services do this already.

Of course, building a nice web interface that is better than the competition is a nice way to stand out. Unfortunately, you're often competing with free (as in FreeConferenceCall) so I guess you have to make something really compelling to make a difference worth paying for.