I was pretty big into anime fanfic so anipike was the web directory I went to. The fan sites via xoom, geocities, tripod, angelfire are linked via web ring. Web ring is like a circle of website with similar interest and individual anime website would have a web ring to help find other similar website within the web ring. https://en.wikipedia.org/wiki/Webring
The ads weren't bad it was banners and it blinks or slide across like marquee html tag. The majority of the web ads felt like print paper ads less scientific like today. Today ads they got metric, funnel, and trying to get more eyeballs on it, very gamey to get your attention which I believe leads to addiction and click bait stuff.
The user involvement was less, social aspect seems to be around hobbies. Now a day you can try to catch up with your friends via facebook, snapchat, etc.. it seems like everybody is trying to get approval by online friends by having that awesome picture while traveling and doing stuff.
There was a famous newsletter I follow for my fanfiction too (rec.arts.anime.creative).