Clue is a free and easy to use Web site testing service.

Some Web sites owners may spend a lot of time and efforts building their portals and not see their labor bear the fruits that they would have expected. It can be that their sites do not get a lot of traffic or they can't transform the traffic that they get into more business. The fact that a Web site is not producing the desirable results can be linked to many causes, like the fact that visitors do not recall much of the site after a visit. If you own a Web site and suspect that may be the case with yours, you don't have to stay idle and hope for the best.
Fortunately, there are some tools available today that allow you for testing your site visitors' memory of your site. Some of them like FiveSecondtest.com are very comprehensive but come at a price. On the other hand, Clue is a free tool from Bay Area interaction design and design strategy firm ZURB, that lets you create a 5-second interactive memory test that you can use to test what people remember about your product according to the New York Times.
Here are how the test works:Go to Clue and enter the URL of the site that you want to test and Clue will take a screenshot of the site and return a link that you can give to your test subjects.
Once you got the results, you can then work on twisting your site look, feel or content to match what you actually want them to remember about you and your product.
The service is free and is mainly aimed at small business and retailers with little time or resources to devote to running a Web site.

For more, see NewYorkTimes.com