DSL, Cable, Satellite, etc.. = Shared or non-dedicated
T1, T2, T3... = Dedicated
Another words your DSL connection does not necessarily run at 7.1Mbps but a T1 line will always function at 1.5Mbps and for a large number of users according to the ISP SLA. T1 you certainly can say is not capable of the max speed your connection is but it will function at a level far superior to any shared connection.
Speakeasy.net says my line is running at 7.1Mbps exactly, and the downloads from many of the sites I go to prove it, and I run tests two times a day, during non peak hours and deep into the peak hours. I have just as much upload as a T1 and the upload stays constant all day as well. So shared connection, it doesn't feel like that, especially when hosting large game servers, even though it is shared, I am one of the only users that really has DSL in this area. There are a few other people on the DSL network as well, but everyone else has Cable.
Also, T* lines are shared as soon as they are off the T* provider's network, more importantly, once it's on their backbone, so it's just like my DSL except not shared over an area, but shared over a backbone.
