They differ in cost/speeds/availability/security/etc... C|net has a nice comparison over here In my area, only DSL is available... the funny part verizon is the phone company and they charge WAY TOO MUCH for the dsl service, and it's capped... whereas Earthlink gives u all the potential available and is cheaper/similar to the verizon fees... so in conclusion pia, it all depends... some companies like Comcast, offer good combo packages (internet + cable tv) heck even DirectTV are offering some (internet + tv) services.. so if all services are available then it comes down to the speed/cost ratio ..