Explore works in mysterious ways, but it does depend on how many views/comments/favs in a certain time period from posting the image. More groups = more comments, views etc, and make sure you tag it up well, as this also contributes.
Chris I know, will disagree with the groups.
I'm not keen on some of those horribly butt-licking "rate my picture" groups that people use to boost their view/comment ratio, but I think sticking them in the groups for lens / camera / location / whatever is really useful. I've spent many an hour loading up a group and just clicking "slideshow" and enjoying what is on offer for a particular lens or location. In the long run I think tags are the key though, about 70% of my hits are coming through Yahoo! Search now.
Got to say it again though, really
really impressed with your 365 so far, lots of clever ideas already, I'm almost wishing I had a 'theme' to stick with as well.
Day 6 for me...
Thought about cleaning the windows, but that kind of goes against what I'm doing with this, so I 'kept it real'. I'm going to do this once a month until I perfect it, although living in a rural area doesn't help with the light trails etc, need about 20 seconds to get a reasonable amount.