>Share your idea, it’ll validate (or invalidate it), shape it and most importantly, commit you to it. We don’t want to let people down and we do want to save face, so tell people what you’re working on.
I'm not sure if I agree with this last point. Studies have consistently shown that discussing a goal with others reduces your motivation to actually meet the goal[0]. I've found this to be true in my own experience with side projects. I'll spend a few days excitedly discussing the details of some idea with my friends online, and then never end up finishing the project.
Social pressure does work, but it's likely better for more definite goals. You could tell your friend "You know, I think I'll run that marathon with you next month," and be obligated to prepare for it. However, side projects are mostly self-motivated and there's no use sharing all your excitement with friends instead of working on something tangible to show.
[0]: http://www.newsweek.com/does-announcing-your-goals-help-you-...