a couple initial thoughts:
-fivesecondtest was the first thing that came to mind when i checked it out (before reading your blurb) so glad to see you guys aware of the market.
-as opposed to "rating" initial impressions, i'd focus on the oft-used phrase, "initial impressions mean everything" as a part of the pitch.
-is there any way to delay the signup proces for after an initial look? i think a number of people who would otherwise be willing to check it out are turned off by having to sign up for another site off the bat (and i imagine a number of the HN community would agree with the sentiment)
-i think goodreads & lulu would provide great opportunities to leverage their existing communities...maybe future partnership with the latter?
hope that helps!
Regarding the sign-in... because we're building a community of readers and writers who are really only interested in giving or getting feedback, we want to ensure that users are committed to having an identity on the site -- which at a minimum requires a display name and an email address.
Same goes for almost any popular blog -- and HN and Twitter... you cannot post or submit comments without providing a few key personal details. We do like the common suggestion here that perhaps we can implement a 'gradual engagement' model, whereby people can read a few pages without rating them.
Your product isn't your website, although at the moment you may feel it is. Your product is the people who are going to spend their time to do these tests. The harder you make it for them to achieve that, the less "product" you have to sell.
Your website is going to need the network effect of many viewers to make it worth people signing up to submit their work. I don't think you can achieve that with a signup for people just wanting to check it out. You're going to get a lot of traffic from twitter, facebook and other social networks, and those people aren't going to sign up just to "check it out".
To put that in perspective, our two biggest regular referrers for Fivesecondtest.com (other than the occasional article write up) are Facebook and Twitter (around 25-30% of traffic). Yet both combined account for less than 6% of our signups. That's a lot of traffic that participate but have no intention of signing up. Of course, we may be missing an opportunity there :)
The worst thing you can have is a situation where you have more tests than you have testers. We've been keeping an eye on ClueApp (a direct copy of Fivesecondtest.com) and they suck at this. Unless you tweet your test, you can except to get zero results (and most people won't do this). The biggest challenge you face is ensuring you have enough people doing tests to cover the expected results. The first time a writer gets "zero" feedback after 24 hours, they're gone never to return.
Aside from that, my main issue is that you have this big green call to action that says, "start reading", and I have this expectation that I'm going to jump right in. So I'm excited and ready to go; instead I'm shown that this is an exclusive club that I need to be a member of. I'm not that committed. Ctrl+w.
Otherwise, love it!