There are some movies franchises where the studio will carefully await box office numbers before deciding whether or not to go ahead with another sequel, and then there are the other kind. The Amazing Spider-Man 2 isn't out until next summer, but Sony has already greenlit The Amazing Spider-Man 3 and The Amazing Spider-Man 4. They even have release dates set already, all the way up to 2018 - now that's planning ahead.
It's important not to underestimate just how lucrative the Spider-Man property has been for Sony/Columbia. In terms of box office take, it is the most successful franchise in the company's history, even more so than James Bond, with all four films netting a combined gross of over $3.2 billion. In the light of the storming success of Marvel/Disney's shared movie universe model, the idea of expanding The Amazing Spider-Man into spin-offs as well as sequels probably holds a fair bit of appeal for Sony.
The latest buzz with regards to the spin-off idea comes from Sony co-chairman Amy Pascal's presentation to investors that took place this week, during which she touched on the subject of the Amazing Spider-Man franchise and its future. Specifically, Pascal alluded to future characters from within Spider-Man's orbit whom Sony hopes to add to their roster. According to TheWrap, Pascal stated that, "[Sony is] going to access Marvel’s full world of Spider-Man characters, so be on the lookout for new heroes and villains."
It's a promising but frustratingly vague statement, yet it's been enough to spark a lot of discussion about whether Sony will attempt to milk the success of Spider-Man and the current craze for comic book movies by expanding the universe into spin-off titles as well. Sony owns the rights not only to Spider-Man, but also to his allies and foes, so if a standalone movie about (for example) Spider-Girl was to be made, then it would be under Sony's care.
Sony is slightly more limited than other studios currently producing movies based on Marvel comics, at least in terms of characters who could feasibly star in a successful spin-off. Whereas Marvel/Disney has a massive pool of characters to choose from and Twentieth Century Fox owns not only all of the X-Men but also the Fantastic Four, Spider-Man really is the only high-profile superhero that Sony owns the film rights to. His most common allies are usually big enough that they have their own comic book series and, as a result, their movie adaptation rights lie elsewhere.
Still, Sony certainly isn't wanting for super villains to pick from, since Spider-Man has plenty of foes, but it's a lot more difficult to sell a standalone movie with a villain as the protagonist and the bad guys Pascal mentioned are most likely members of the Sinister Six who are being lined up for The Amazing Spider-Man 3 and The Amazing Spider-Man 4.
If an Amazing Spider-Man movie spin-off does happen, however, then the most likely candidate right now is Venom. Last year franchise producer Matthew Tolman has explicitly said that the anti-hero "deserves his own movie" and that the idea of a Venom spin-off has come up in discussions with a generally favorable response. Zombieland writers Rhett Reese and Paul Wernick penned a treatment for a Venom movie several years ago (that unfortunately never made it to the screen), and The Amazing Spider-Man 2 co-screenwriters and producers Roberto Orci and Alex Kurtzman have expressed their enthusiasm for the character, and for the idea of making an anti-hero movie.
While Pascal's words don't guarantee anything, they do suggest that Sony is seeking to expand the Spider-Man franchise. While we wait for actual news of spin-off movies, however, there's always the short Venom fan film Truth in Journalism, which stars Ryan Kwanten (True Blood) as Eddie Brock.
The Amazing Spider-Man 2 opens in U.S. theaters on May 2nd, 2014, followed by The Amazing Spider-Man 3 on June 10th, 2016 and The Amazing Spider-Man 4 on May 4th, 2018.