You definitely need a tagline on what the site is doing straight below the TOP LEFT corner. No many people will click into the "what is zipalong" link.
If I didn't get to the site from YC news, I will think that it is just another photo site rather than a travel site.
It's clever that you put the logo at the top right corner. But, it may hurt the usability because users tend to think that logo should be at the top left corner of the site. It is good to innovate but sometimes it is even better to follow the norm since most of the sites put the logo at the top left corner.
Anyway, I have no time to review the site now. I have to leave my office now. Will let you know once I get back to my home.
I like the design (though perhaps a bit gradient-heavy, I prefer flat) but you should definitely add some sort of tagline, or at least put the "what is zipalong" link in a different color or something; I didn't even see it the first time I opened the site. Just seeing a login form, I immediately closed the tab. Good thing I read the comments, because this looks really cool.
One small usability tip: you could pretty easily combine the login and registration forms. Just put an extra "register" button, do a username check, then add a second password box and the name fields. Also, it'd be a little nicer (though I see what you're doing with the in-one-line thing) if you stacked the password confirmation box under the other; I usually visually compare the lengths before hitting "enter".
Also, I noticed that the look and feel is in many ways similar to Flickr, especially the colors. I don't know if that's a positive or a negative; on the one hand, it will immediately associate your site with photography for anyone who's used Flickr before, while on the other hand it may make it harder to establish a unique brand.
I haven't explored the inside of the site much, but from what I can tell, you've done a pretty good job. Keep up the good work, and good luck.
If I didn't get to the site from YC news, I will think that it is just another photo site rather than a travel site.
It's clever that you put the logo at the top right corner. But, it may hurt the usability because users tend to think that logo should be at the top left corner of the site. It is good to innovate but sometimes it is even better to follow the norm since most of the sites put the logo at the top left corner.
Anyway, I have no time to review the site now. I have to leave my office now. Will let you know once I get back to my home.