SEO Toolbar

These SEO toolbars add SEO features to your web browser.
SEOquake screenshot
Price: free | Requires: Firefox/Chrome/Opera/Safari | Tags: seo toolbar
SEOquake's SEO toolbar is a plugin/extension for Firefox, Chrome, Opera, and Safari that shows a webpage's PageRank, Alexa ranking, and other SEO data. Features: create your own parameters, highlights nofollow links, check and compare URLs, and parameters can be turned on/off.
MozBar screenshot
Price: free | Requires: Firefox 3.6+/Chrome 2.3+ | Tags: seo toolbar
MozBar SEO toolbar, by SEOmoz, provides access to SEO tools and data on your web browser as you surf the Web. Features: Google, Yahoo! and Bing data, nofollow, followed, internal, and external links, compare link metrics, expose page elements, access SEOmoz tools, and custom searches.
SEO Toolbar screenshot
Price: free | Requires: Firefox | Tags: seo toolbar
SEO Toolbar Firefox plug-in helps you analyze many marketing data points directly from your web browser. Features: PageRank, .edu links, .gov links, Dmoz, Yahoo! Directory, BOTW, Archive.org page age, see Whois data, site links, page links, traffic estimates, highlight nofollow links, export data, rank checker, SEO tool, and feed reader.
WebRank Toolbar screenshot
Price: free | Requires: Chrome/Firefox/Opera/Safari | Tags: seo toolbar
WebRank SEO toolbar offers SEO data in your web browser to help you analyze webpages. Features: Google Pagerank, Alexa, Compete and Quantcast Rank, pages indexed and backlinks in Google, Bing and Yahoo!, Whois, geo-IP location, traffic graphics, SocioMeter stats, and website security check.
Affilorama SEO Toolbar screenshot
Price: free | Requires: Firefox | Tags: seo toolbar
Affilorama SEO Toolbar, by Mark Ling, provides SEO data in your web browser to help you analyze domains and webpages. Features: Google PageRank, Alexa Traffic Rank, Complete Traffic Rank, Google and Yahoo backlinks and indexing, nofollow links, onpage details, link scanner, domain info, and Whois info.