I think that there should be a little message that either pops up, or just shows up after you log in. That lets you know that someone has commented on your profile since your last log in. Because when you log in your still on the main page, and you don't know if someone has commented on your profile unless you go to your profile to check.
I think that it is a good and bad idea. That idea would be helpful but, in my opinion, it would get really annoying if it just kept poping up like that.
Well, it could be a choice if it popped up. Even a little notification next to your username at the top of the page would be nice. Like a box that says 1, 2, 3, etc. As to how many new comments there are since you last clicked on your profile.