The Famitsu blog has revealed 3 screenshots of some of the network features to be included in Super Street Fighter 4. Click thumbnails below for larger version of images.
This screenshot is from the new replay mode. From the screenshot you can see that you now have far more options than what was available in the original. You can now select channels to filter replay types.
This is a screenshot of a new lobby type for the replay mode. In Super Street Fighter 4, you and your friends can now jump into a lobby in the replay mode to watch replays together. Voice chat is enabled so that you can talk amongst yourselves as you watch your selected replays or argue over what replay to watch next. It appears that up to 8 players can join this type of lobby.
Here's a translation of the left-side Japanese menu options. Thank you to Takari in the SRK forums for this translation:
Display Player Information
Game Card (!)
(And right top corner, TEAM BATTLE / Lobby)