The ex-superhero turned detective will indeed debut in 2015!
After some confusing and contradictory news from Marvel and Netflix (which suggested we might have to wait until 2016 for the series), Netflix has confirmed that the series will be part of their Fourth Quarter 2015 lineup.
The series will "delve into the dark, gritty" world of superheroes, with potential for crossover with Daredevil.
How does Jessica Jones fit in with the rest of the Marvel universe?
Played by Krysten Ritter, Jessica is kind of odd because she's a non-superhero hero. When she was introduced in the comics, it was after she had already retired from the superhero business (after a traumatizing run-in with The Purple Man, placed by David Tennant), leaving her identity as the hero Jewel behind. It sounds like Netlfix is going to run with this theme, introducing Jessica Jones as a detective in Hell's Kitchen.
She and Luke Cage (played my Mike Colter) are a Marvel comics power couple, so it will be interesting to see their relationship adapted to a thirteen-episode format. Initially Marvel has planned on developing a Jessica Jones show for ABC, but opted to work with Netflix instead. Since they did such an excellent job with Daredevil, I can't fault their decision. Besides, season 2 of Agent Carter already has the time slot to replace Agents of S.H.I.E.L.D. on TV, so there's no reason to add a third Marvel show to the lineup there just yet.
Is this the beginning of a new direction for Marvel?
Jessica Jones is more similar to Agent Carter. than anything else, but even then they have very little in common. She's not part of any team (Like AoS or the Avengers), she doesn't have a superhero identity (like Daredevil), and unlike Agent Carter she's not strongly attached to any other hero. She's got a passing relationship with Daredevil, but she didn't get her beginning there. She really stands alone.