Time was, UHub had a system for letting you get notified when somebody replied to your comments. Then, that just stopped, weeks, maybe months ago (I didn't notice until somebody asked me about it a few days ago, and I realized I'd somehow deleted the software that handled it).
E-mail notification's back on. I've set the default to "off" (don't want to send somebody e-mail they don't want!). There are a couple of ways to get it back on - and to be notified of posts in certain categories: Read more.