The TridentScan commenting system is designed to be a simple replacement for Haloscan comments, after they became unsupported. Some people want a simple, platform neutral commenting system, and there doesn't seem to be another one.
If you want to use the system, that can be set up, and as we have just moved to the version 2 of the system, setting it up for extra sites has become a lot easier. We're looking specifically for beta testers at the moment - we're fairly sure the system is stable (it's in use on two production sites) but we want to make sure everything is OK before opening it up.
If you're interested, drop me a line - tridentscan at jaggedseam dot com.