Neutral Tandem closed its acquisition of Tinet on October 1, 2010. According to the PR, that makes NT a top 10 global IPv4 backbone provider and the number one IPv6 network worldwide. I would have thought that NTT/Verio was the number 1 IPv6 network in the world. NTT has been doing IPv6 a long time.
Neutral Tandem now operates 14 Ethernet Exchanges. Instead of NNI's (network-to-network interfaces) to get from CLEC 1's network to ILEC 2's network, the Ethernet Exchange is suppose to handle that. That means you can get a leg from CLEC 1 and connect to a leg on ILEC 2. It also means that the exchange will be native Ethernet, not TDM converted.