I'll copy this from the other thread:
I could be wrong, but this is how the situation looks to me:
Marvel wanted to use Spider-Man, particularly for Civil War, but they didn't want to use Amazing Spider-Man version/continuity.
Sony saw the lukewarm reception to their franchise and wanted to turn around their fortunes.
The solution was to make this deal.
Marvel gets to use Spider-Man in their movie (presumably Civil War) and they get to use him for free.
In return, Feige & Co. help Sony right the ship, again for free. They help give direction for Spider-Man, using the Marvel "golden touch," for lack of a better term. Plus it is assumed that Spidey will now get a boost in popularity by connecting it with the MCU.
Now it could be as basic as that. Marvel got to use Spidey for its film and Sony now has a revitalized franchise. Sony then continues making new Spider-Man films with this new direction. Hopefully they learn a thing or two from Marvel and the director in charge of the franchise is put in place by Marvel's suggestion and knows what he is doing. Then Marvel may have to make future deals for using Spidey in future MCU films (or TV shows).
Granted, that's not what we want, because it doesn't guarantee that Sony will not interfere again or start having ideas down the line that don't mesh with Marvel's vision.
My hope, barring Marvel regaining the rights or Disney buying Sony, which could be ultimate goals, is for Sony to learn from Marvel and set up a good working relationship in which they come to mutual decisions to keep the the franchises running smoothly. And from history, I'd say it should defer more toward the Marvel way.