1. SEO Site Tools
With this extension you can view just about everything you need to know about a website.
There are 6 sections: external page data, page elements, social media, page terms/tools, server/domain info, and suggestions.
Use the integrated HTML and CSS validation tool to see any errors.
There are way too many features to list, but you can be sure that you'll get plenty of use out of this tool.
2. Sorezki SEO Plus
Sorezki SEO Plus contains 3 sections: stats, optimization, and tools.
Each section has its own set of tabs with useful information. Under stats you can see information pertaining to search engines and social activity regarding the website you're on.
Optimization is where you can see page elements, server/domain info, keyword density, and recommendations.
The tools section lets you do page load speed test, check for plagiarism and more.
3. Chrome SEO Plus
If you're only looking to access core SEO stats quickly, you'll love Chrome SEO Plus.
For any website you can quickly view key metrics like Alexa rank and Google page rank, number of backlinks, social media shares (Delicious and Digg), and site info (IP Address and server location).
4. SiteTrail
With SiteTrail you don't have to worry about an extra icon crowding up your browser because it works from the right click menu.
When you're on a website that you want to know more about, simply right click anywhere on the site and select SiteTrail from the context menu. A new tab opens with information like estimated value, estimated revenue, estimated pageviews, rankings, site traffic, site server, DNS records, HTTP headers and Whois information.
5. SeoQuake
SeoQuake is a search engine enhancement tool that works on Google, Yahoo and Bing.
You can see information about pagerank, Alexa rank, Yahoo links, Index info (Google, Bing, Delicious), web archive age, nofollow links and more, for any of your search results.
At the top of the search results, you'll notice the SeoQuake navigation bar that lets you sort your search results by pagerank, age, indexed links and more. From the browser icon you can also click to view an in-depth keyword density analysis for any page; results open in a new tab.
