The first inFAMOUS was released with 99 playable missions.  The number of missions the sequel will have depends on you.

In a new trailer released for inFAMOUS 2, players will have the opportunity to create their own missions for the title.  According to the trailer, players can create defense, escort, search and destroy, and survival missions.  These basic setups will then work as building blocks to create many other missions such a platforming and even stealth missions.

And these missions aren't just for you alone to enjoy.  Once created, you can upload them to the PlayStation Network, so other players can take part in them.  From the looks of the trailer, it seems green nodes will appear in game signifying a starting point for the user-created missions with the creator's name under it.

"We thought inFAMOUS 2 would be better if it didn't end-if you never ran out of missions and mini-missions to play and things to do." said Chris Zimmerman, development director at Sucker Punch Productions, in a post on the game's website.

There will also be a limited public beta for the game's user-generated content.  The beta is set to go live in early April.  Details to sign up for the beta will be available March 14.

The game is set to release June 7th.