You should really grab someone off the street and seat them in front of your app, with a notebook or recorder in your hand.
You seem to have done a good deal of work, and have some neat stuff. However, after a couple of minutes digging, I can only surmise it's about hiking trips, and it should somehow be possible to see foot trails - if I could get the inscrutable markers to do something ...
I do certainly do some "man-on-the-street" testing :), but, I'm always looking for more feedback just like yours.
I'm sorry I dropped you on this page for your first go. You might find the experience of using the site less confusing if you go to the home page: http://www.trailbehind.com. There is a legend for the markers, and we display hiking trips. This page is just for adding data to the map.
In response to your bugs:
1) I should add the home page legend to this map, which is no problem, just an oversight
2) There are trails on the map, at zoom level 15 and above. We're working on showing them earlier, but browsers choke on our method of display right now. We have many ten thousands of GPX files indexed.
Yes! I am working on a feature that merges a GPX track with a Flickr set based on timestamps. One of the sites we index to our map actually does something similar: www.everytrail.com. They merge tracks with photos, but don't use Flickr.
Also, we already show Flickr photos for places on the map via the Photos tab. We are typically be able to show photos of places based on that alone.
You seem to have done a good deal of work, and have some neat stuff. However, after a couple of minutes digging, I can only surmise it's about hiking trips, and it should somehow be possible to see foot trails - if I could get the inscrutable markers to do something ...