Website Grader - Grade your website's strengths and weaknesses in seconds.
Skuuudle - Discover, match and monitor your eCommerce competitors.
PageSpeed Ninja - One-click page speed boost for WordPress
Price2Spy - Price2Spy is a price monitoring, pricing analytics, and repricing tool, meant to help eCommerce professionals keep an eye on their competitors or retailers.
WebSite Auditor - The techie's SEO spider: find site issues other tools miss
BuiltWith - Find out the technology behind websites