I just replied to a client asking what I though about a website grader that was used to review is website. My comments are universally true for anyone use website grader tools.
I just took a look at http://www.amivisible.org. I've not seen this site before.
I think most of these "Review" websites have something to offer. Google has many criteria used to determine if you are Content Rich, and a good resource for visitors. It's a life-long campaign to continually be fresh on the Internet, so Google and other search engines will notice you, and give you high search results placement.
I would't get too emotionally involved with a Grade that these sites give. It's a bit like saying if Google's own PageRank system gives your homepage a 4 out of 10, then you must be doing poorly. When in fact, a 4 is very good.
What I personally do is review the reports, and things I know I can reasonably do, I do them, but I don't worry about getting a perfect score, because if I go to a different website grader, they will use different criteria, and the scores between the two site will not even be close. It's a game these companies use to get your SEO business. That's how they make money.
The guy we use for our SEO is Taylor Reaume, www.thesearchenginepros.com. He uses professional grading tools and decides what needs to be done to improve the performance of the site. Then he has other tools to that make it easy to promote your site. Some of these tools are free, you just need to create a free account.
rinconcatering.com Customer Reach:14% - http://www.amivisible.org/
A more respected tool is, http://websitegrader.com/
On this site you scored a 76. Should make you feel better ;-)
To improve your scores, someone in your company needs to occasionally do things they know will help promote the site 1) add optimized articles to your blog, 2) post your website profile on directory sites 3) re-purpose your articles to social networking sites. These are the top things you can do to promote your site. If you don't have time to do these things, or don't want to learn, you can always hire a professional, like Taylor.
This website, www.site-ninja.com scores a 97 at Websitegrader.com. Yahoo!! I also know that I shouldn't get emotionally connected to a good score either, http://websitegrader.com/site/www.site-ninja.com
Hope that gives you some perspective,