I recall NetWits, a multiplayer 1950s-style quiz show game on MSN where you played as a contestant against other MSN subscribers in real-time (there was a scheduled "broadcast time" every weeknight -- couldn't play at any other time). There were real prizes, like trips from Expedia.

Here's a video of it: https://www.youtube.com/watch?v=Uyje8xlGc9Q

Truly a product of its time, but they really tried to experiment with multimedia (at least in MSN 2.0). I think there was an online version of Encarta and a bunch of other things that I've since forgotten.