Potpourri IV - Hints

I've seen a lot of good thinking going on around Potpourri IV, but there are a few questions that have stumped everyone. So to help move things along, I'm going to give hints for the harder puzzles.

The following disciplines are reflected in at least one puzzle: Math, Geometry, Logic, Literature, General Trivia, Puzzle Trivia, Physics, Biology.

1. No hint.
2. This is not a mathematical puzzle; it's a puzzle puzzle.
3. No hint.
4. There was an older URL before wx3.com
5. This point of light was, quite literally, sent as a message bearer.
6. To find out which doesn't belong, find out what they all have in common.
7. Hmmm...
8. No hint.
9. No hint.
10. No hint.
11. No hint.