Ask the Lost Six is a tumblr based around an alternate Mane Six consisting of some of the more famous background ponies. It is drawn by =the Doctor=.
It was officially declared over in May of 2013.
The blog focuses on six background ponies who created a blog soon after meeting. The six are:
Vinyl Scratch (aka DJ-0N3)
You will find each of them answering questions at the laptop, but they also have lives away from the page. Each one tends to have something important designated to them. Octavia writes the ongoing story that the Tumblr is based around. Lyra draws pictures that are occasionally posted. Vinyl Scratch (aka DJ-P0N3) does the digital imaging. Spitfire works on this wiki. Bonbon is taking music lessons from Vinyl Scratch, and posts an occasional song. Derpy organizes the mail and finds out about new events. As questions are asked, the world around them is fleshed out and secrets are learned. Therefore, the more questions asked, the more defined their world will be.