It's a good challenge in that 1. it is positive. 2. it can apply to any/all fandoms 3. I thought I knew everyone in fandom, but yesterday I realized I was wrong, so new people 4. it encourages you to read a bit more, reach out a bit more, and make connections that you wouldn't otherwise.

No down-side except that because it is 15 days some of the day's challenges can get a little overlapping. But so far, I'm enjoying it.