At the Blogher conference two weeks ago i spoke on a panel on How To Measure Social Media ROI with Katie Paine and Lena West. One of the things that we discussed was the growing importance of monitoring Blog comments and using them as one of the aspects of measuring the success of your blogs. During the panel, i commented that you also have to understand your audience, will they leave comments, it is easy for them to do so (or do they need to sign-up like for example HP blogs), are they afraid to engage in public because they are afraid to speak on behalf of their company, etc. From my own experience, I still get a lot of e-mailed comments especially from clients on blog posts.
The Net-Savvy Executive has a recent post on Measuring blog comments that hits on that same subject and mentions some companies that allow you to search comments and others that allow tracking of comments that can then be incorporated into measurement techniques companies put together as part of their Social Media strategy. I agree with Nathan that vendors in this space are aware that tracking and measuring comments is important. This topic also came up back in December when Factiva hosted a Social Media Roundtable event in Palo Alto to gather feedback on what should be measured.