Yes, I actually did that myself at one point, before I realized that it wasn't allowed. (I then deleted that "review.")
However, when authors do take the time to create review reply threads here on the forum, or use the Promote a Story thread, or otherwise make their presence known in some way, it helps readers connect with them. Case in point? Magusfang. His review reply thread is lively, he and his readers chat in the shoutbox, and you can see the interactions drawing in new people. Of course, you can't make people respond to a thread you create, but his personality comes through his posts, and that works for his readers.
I've been making review reply threads (and putting the URLs in the text of the stories) ever since I first heard of the idea, but unlike Magusfang's readers, most of the people who regularly review my stories don't seem to have forum accounts. With the exception of 2 people (Jomahawk and FairySlayer), I have no idea whether anyone has ever read my replies to their reviews.
It probably doesn't help my cause that I write a lot of very different types of stories, which means that readers who loved my last story may hate the next one and not bother looking at the one after that. Come to think of it, there probably aren't many successful professional fiction writers who write in a lot of different genres. How many people would buy a romance novel by Clive Barker or Laura Hillenbrand?
I also never hang out in the shoutbox, and I'll confess that the main reason why is fear that it will become an addictive, time-sucking activity. I have enough temptations of that sort already. But maybe if I get everything on my To Do list done today, I'll give it a try. That might be a big if, though.
Anyway, given all that, I guess I'm pretty happy to have as many regular reviewers as I do. I'm also happy that a good portion of them go into detail about what they liked or didn't like. So I can't complain too much.