Welcome.
You can find follow-ups to your comments by clicking on the red envelope under your karma score. I found out about that by asking-- it isn't what I'd call an intuitive interface.
Thank you, I'm aware of that. But that still requires a person to be a pretty obsessive user of this site. Unless I have a lot of free time (like today), there's no way I can go back and check every single site where I've left comments and see how my comments are doing. At least LW aggregates reply comments to my input, but that doesn't solve the bigger problem of me having to come back to LW in the first place.
It's also worth noting that this comment interface is difficult to use in many places with slow/bad connections, like, you know, the entirety of...
Some research says that lurkers make up over 90% of online groups. I suspect that Less Wrong has an even higher percentage of lurkers than other online communities.
Please post a comment in this thread saying "Hi." You can say more if you want, but just posting "Hi" is good for a guaranteed free point of karma.
Also see the introduction thread.