Right, I'll go first.
1. What do you like in a photo?
Lots of things. Spectacular scenery, humour, symbolism. Sometimes I can just appreciate the technical ability of the photographer, or the imagination they had in composing that scene, or realising that that very moment would make a great photo.
Technically, that's pretty easy. Climb a very very very long ladder, point and shoot. But it's the setting that makes it.
Yes, it's just an old man. Nothing exciting, but you have to admit it's a great photo.
It's just two elephants, but it says so much more.
Many things determine what we like and that can vary from time to time and situation to situation.
2. How do you vote for a photo?
It changes. Quality is important (like focus, no heads cut off, composition), beauty, whether it was difficult to do, imagination. Sometimes, if they're very similar (e.g. the water theme), I just go with my gut, because I can't separate them any other way.
3. What do you like about the challenges?
I have to admit the most memorable ones were where I had to work at it, such as driving around the countryside for an hour looking for something abandoned (I found a dumped TV), or I spent half an hour at a roundabout one night, trying to get a long exposure shot of car lights. And failed. Granted, I haven't done much of this lately.
4. In what way do you think the monthly challenges could be improved?
Changing the rules so that photos have to be taken for the challenge is probably a good idea, that few would object to. It would make it a little more interactive, perhaps, where we could share stories of our adventures. We would have to rely on everyone's honesty, but I don't think that would be a problem.
One possible way to ensure this would be to set a challenge that rules out most of our already-established photo albums, such as a photographic technique.
Two examples that I saw when trying to find a theme myself...
Lens flare
(I don't like it much, but I've seen it)
Or long exposure
The latter is available to most of us on our standard digital cameras. Challenges like this might have the added bonus of forcing us to find out what all the other functions on the camera are for (I only found out about long exposure for the Light challenge).
So, just some thoughts. I've only added them for the purposes of debate, and none of this is a slight directed at anyone in particular, for I'm no different to anyone else here. Please add some more thoughts. (happy smiley, as the software won't let me add another image)
Edit: of course anything we suggest must be do-able without special equipment, although if you have it, you can use it e.g. big lenses