Hah, thanks for the great review Norm! This is pretty much stelth mode, but it's just a simple wrap for the Web21C Web services. There are a bunch of people exposing telephones onto the Web in various shapes and forms, and that's great because it's creating a market the old school cannot ignore. We're breaking down the walls of The Ministry of Telco! What's great about BT is this is very much just a toe in the water, and if it "works" we've a ton of great stuff to release onto the Web so people like yourselves can build silly and useful stuff. Fun times ahead!
Like Gabe mentioned in an earlier comment, Lypp offers a similiar service with the additional feature that you can drive it via IM.
Looking at it the lypp and mojo security models seem pretty different.
Lypp just wraps basic authentication, whereas from what I can see here mojo has stronger security model. I wonder if BT are considering oAuth?