Traditionally, VoIP providers have been the pipsqueak upstarts, like Vonage. While they have the cool-ness factor down cold, they lack the resources and wherewithal to endure the regulatory fever swamps of the FCC and the states. (See, e.g., the VoIP E-911 mandate). EBay, by contrast, does have those resources to fight the regulatory fights, if it so wishes.
While still a babe-in-the-woods compared to the closely-regulated veterans of regulation like the cable, broadcasting and telephone companies, EBay's muscle as a VoIP provider could be determinative in battles concerning the regulation of VoIP, as well as issues like 'net neutrality.'