Answer:
These are tools that tell SEO's information about a website such as PageRank, monthly traffic, # of backlinks it has, etc. There are dozens of different tools that you can use either hosted on a website and ones that come in the version of downloadable toolbars such as the Google toolbar.
SEO is the short form of Search Engines Optimization.Peoply of web world allways trying to know more about Seo. Different people have different views about seo. Seo is the way to increase the website rank in the search engines like as Google,Yahoo,MSN.com.
Well there are many SEO tools available now a days.I have used Gostats.com Hit counters on many of my sites and blogs and it offers comprehensive and real time tracking. google adward tool for keyword tracking,Google Back link Checker tool,which enables you to know the number of websites who have given a link to your website or webpage and blogs,Rank checker for checking ranks, etc.