Sorry, I'll take a dif viewpoint. I discovered this feature months ago but don't click on it cuz I felt like I was 'spying' on the person & that made me feel very uncomfortable.
If you want to know who's online, heck all you have to do is click on Forums & at the bottom of the page (along w/ bdays etc) it will show everyone who is online. But if you want to know what thread they're reading you have to actually go to that option in the listing of fora. And again, it makes me feel like I'm spying on them. YMMV.
Cheers. Sharon