Marketing_Guy - 1:50 pm on Jul 18, 2012 (gmt 0)
Perhaps testing out a spambot? Could be scraping posts from forums (specific users, hence the one-sided conversation) and posting it to review sites? With a little effort I guess it wouldn't be that hard to match subject areas to come up with comment spam that might fly under the radar of even eagle-eyed admins.
Come to think of it, I have seen a slight increase in blog comment spam in recent months with comments that seem human written, but just don't fit into the context of the blog post.