Are they going to start a new trilogy of Spider-Man once again?

Sony released their first three Spider-Man movies between 2002 and 2007, and already had a 4th & 5th Spider-Man in the works.

After the success of the Avengers franchise released by Marvel Studios, beginning with Iron Man in 2008, there was suddenly a lot of interest in Marvel property. Sony tried to push the Spider-Man franchise to be bigger and better in order to benefit from the renewed interest in superhero movies, and tried to rush the production.

This caused the director (Sam Raimi) to pull out of creating more, as he didn't want to complete it to their timeline and other creative differences (casting choices, doing it in 3d).

This forced Sony to do a reboot with Marc Webb and Andrew Garfield with The Amazing Spider-Man. This was supposed to kick off its own franchise with the emergence of Spider-Man villains The Sinister Six, but the movies failed to impress.

Due to their attempts at rebooting the franchise failing and Marvel's going on to have such success, Sony struck up a deal with Marvel. Marvel would be allowed to use Spider-Man in their other Avengers movies, whilst in exchange they would help Sony creatively in writing new Spider-Man movies.

One of the conditions that Marvel required for this deal was to recast the actor for Spider-Man (not sure about the director), which meant that for further films the continuity would not hold, hence them again rebooting the franchise.

Whether these new films will again have an origin story is uncertain so far, or if they will begin at a time when Spider-Man already has his powers.

If the question is why they are rebooting Spider-Man so soon after the previous attempts, Roger's answer is correct, if no more movies are made in a set time frame the rights to Spider-Man reverts back to Marvel.

It's just for business. Sony's retention of the rights to the Spider-Man franchise is contingent upon them continuing to make movies. If they stop making those movies, the rights can be contested and reverted back to Marvel, and then Sony has lost that particular revenue stream.

This has happened before, such as with the original Fantastic Four movie. Not the 2005 one, the 1994 one that was made on a shoestring and never released, simply because a movie had to be made or the studio would have lost the rights.

Yes, they are "rebooting" Spider-Man, but it will not be a third, new attempt at a trilogy the way the previous two series were.

Sony is rebooting Spider-Man because their last attempt at a series did not do well for them financially. Legally, they have to keep making Spider-Man movies every so often, or they'll lose the rights. But the quality of the movies was not up to the same level as the Fox or Marvel movies, so Sony decided to make a deal with Marvel. Marvel will assist Sony in production of the movie, and Sony will allow Marvel to bring the character into the Marvel Cinematic Universe (e.g. he's going to appear in Captain America: Civil War).

Part of the deal is that Sony is going to make a Spider-Man movie in 2017 that is unconnected to either Spider-Man and The Amazing Spider-Man. They have re-cast the role and will be telling an entirely different story. But, this is not just "another rebooted trilogy." There are a number of things that are different about this:

• It's not a stand-alone movie the way the previous two were. Rather, it will be part of the overall MCU, which contains the Avengers movies, the Daredevil Netflix show, Agents of S.H.I.E.L.D., etc. The Spider-Man from Civil War will be the same character as the one from the Spider-Man movie.

• It is not an "origin story". Spider-Man already exists in the Marvel movie universe, we just haven't seen him yet. In the movie, Spider-Man will start out already having his powers and already behaving as a costumed super-hero, just an "amateur" one.

Kevin Feige, the President of Marvel Studios, confirmed this pretty soon after the reboot was announced:

"In Spider-Man’s very specific case, where there have been two retellings of that origin in the last whatever it’s been - [thirteen] years - for us we are going to take it for granted that people know that, and the specifics,"

"It will not be an origin story,"

"There is a young kid [already] running around New York City in a homemade version of the Spider-Man costume in the MCU, you just don’t know it yet,"(^src)