I did also really like the IMDB forums and thought it was stupid they got rid of it. But I did see they rerouted it to another site so I guess its not totally dead. It was cool to read discussion of more obscure or forgotten movies on that thing (like Out Of The Blue by Dennis Hopper.. anyone ever see this one? From 1980)
I don't know what else I'd miss as much.. I guess it was nice back in the day when people would make their own websites instead of everyone flocking to the same corporate apps/websites nowadays on their phone. I also miss minor things like no/less ads on youtube and whatnot but those aren't a big deal really.