Building on the rumours of a Marvel Cinematic Universe without Iron Man, Thor and Captain America, a new report suggests that Marvel Studios would like to someday incorporate Sony's Spider-Man into their shared universe -- and Sony may also be open to the idea.
According to HitFix, Marvel Studios is looking to bring Spider-Man into their Cinematic Universe -- but makes it clear that there is no confirmation of this happening, only reports of early discussions.
Again, this is mostly speculation, but here's the report from HitFix (which has proven to have a pretty good track-record with rumouriffic stuff):
"While I can't get the confirmations I need to verify the story, I'm hearing that there are some very cool "Spider-Man" plans being discussed that would help Sony refocus their enormously important franchise while also opening up some connections in the onscreen Marvel movie universe that would blow fandom's minds. Will it work out? I don't know. I would love to be able to state for sure that it's happening. What seems clear from what I've heard is that Marvel wants to be able to play with all of their characters, and if they can make that work creatively and on a corporate level, they will, and that means the world gets bigger again."
The site also indicates that Fox is less cooperative when it comes to sharing their X-Men characters with Marvel. They seem to be content with their own shared universe, since they're expanding it with a Deadpool movie in 2016.