Around the time of the TNS/Cymfony acquisition and NewComm, Katie Paine commented on the lack of tools to measure blog comments. Since I'm making the rounds talking to the tools and analysis folks, I started asking about comments. It turns out that the tools are out there, if you have a budget.
Actually, you don't need a budget, if all you want to do is find comments; Google search can help you with that. But if you want to measure comments (which is what Katie is looking for), prepare to spend some money. The free blog-monitoring services—and most feeds—miss the comments.
The seemingly simple question about tracking and measuring blog comments turns out to be a little tricky. Some of the companies rely on human analysts to interpret what the automated systems find, so asking what the software measures misses the point. Others focus on qualitative analysis, so measurement really isn't the deliverable, anyway. Some of the companies don't measure blogs, preferring online communities as a source of insight.
CoreX, Integrasco, Radian6, Umbria, and Visible Technologies track comments. As I catch up on the big writing project, I expect to write more about the companies here, and I expect to learn that more companies include comments in their analysis.
The bottom line is that the vendors are aware that tracking and measuring comments could be useful. There are interesting questions about monitoring comments (how many times do you go back for comments, and for how long after the original post?), but the measurements are available.