I'm happy to answer any questions about the website.
Edit: Clever Surveys just received major design improvements, and the registration requirement for submitting responses has been removed!
What about the website makes it look dated? I'm the only one developing the website, and I have no graphic design skills. So user feedback is very useful for me. Also, see my response to Grendel about registration.
I'm sorry, I didn't mean to come off as harsh as I did.. Anyway, about the registrations, that makes sense, I just tried one and it asked me to register so I didn't try any more. About the user interface, there's a couple of things I think might have to do with giving me a dated feel, though that might've just been me. Anyway, I think the navigation bar on top is quite good -- it's clean and simple. I think the footer might be a bit too tall, and that it would feel sleeker if it were a tad shorter. The social bar at the bottom of every page above the footer is a bit much, in my opinion, since you've got social buttons already just below it (in the footer), though those are general. The biggest thing though, in my opinion, that is making it feel dated to me might be the colour scheme -- there's very little contrast, and it makes the website look a bit boring. Colours are very important in web design, and I'd look into incorporating some complementary colours, i.e., that would be some cool shade of light brown -- maybe in the navigation bar and in the footer? Just a little bit more livelier, and complementary colours always look good. Edit: I've been playing around with your css and stuff, would you mind if I posted a screenshot of what I think you could improve a bit on your website? Edit2: I haven't been able to figure out a good colour scheme yet but I think this looks a bit better than what you currently have: 
No offense taken, and thank you for the suggestions. I see what you're saying. The light blue on blue for the main content (or cards as I've taken to calling them) doesn't have enough contrast. Something closer to white (like your picture) will probably look better. I'll have to play around with the colors more, and maybe put up a survey for user feedback. I should be able to shrink the footer on wider screens. It's a fairly new addition that still needs work. People actually use the social buttons a lot, but I'll see about making them blend in more. Also, I changed the predictor list so predictors that need responses won't link directly to the submit response page. This way, users won't immediately see a registration prompt, and hopefully it will be more clear.
Registration is only required to contribute data to a predictor, which makes it more accurate. Predictors need a minimum of responses before they can predict, which is indicated with the "needs responses" tag on the predictors list. I've been playing around with directing users right to the page for submitting a response when a predictor needs more responses. In your opinion, is this too confusing? For reference, the predictor page for the pets survey is: http://www.cleversurveys.com/survey/5709198289534976_5629499534213120/what-pet-should-i-get