Mark is super cool and as respectful and generous with information as anyone I've encountered in the hobby. Seriously a stand-up guy.

To add my personal feeling regarding the guarding of information: A lot of us have considerable time invested in hunting down information and parts. We've incurred a cost in order to obtain parts or information. I spent eight years looking for a particular rare part, and when I found one, I found a few. I emailed friends and those who have helped me in the past to let them know what I'd found and to offer trade for parts they may have. In my case, I wanted to trade my time invested into finding part X for the time my friends had invested to find part Y or Z. This encourages cooperation between people, and allows those who are willing to do the heavy lifting to recoup the invested time. If someone thinks the hobby would be improved if everyone instantly publicly shared whatever information they gather, that's great.
The knowledge someone gains through their own toil is theirs to give away freely. But I encourage anyone who holds this opinion to get busy, walk the walk, and tell the rest of us what the worm hole emitter is.