[polskibus]

There are plenty of vendors that provide good UDP-based solutions, for example TIBCO. In my opinion multicast is not used widely enough, partially because everybody thinks that tcpip pub sub is good enough.

Financial incentives made HFT's and alike go farther than the average software companies - just look at the microwave networks.

[tptacek]

Multicast isn't used widely for a lot of reasons, but the most important of them is that it simply doesn't scale across routing domains.