There are many tools for knowing the performance of your blog or website, where all did your site or blog reach.These tools can be used for knowing the current stats of your site based on various parameters like the Page Rank of your site, Inbound Links, etc.

Whos.Amung.Us

This tools displays how many users are reading your website or blog in real time?Get the code from their homepage.

Website Grader

This web application gives you a website grade based on its own algorithm , gets your Page Rank, Alexa Rank, Technorati Rank, Google and Yahoo Inbound Links, Google indexed pages and Delicious saved count and the last Google crawl date.If you ever got dugg , it gives a count of your posts on digg and the number of posts which made it to the front page.

It also gives you suggestions after analysing your site.It can also do a competitive analysis of your competitors blogs or sites.

PopUri.us

A tool to check at-a-glance the link popularity of any site based on its ranking (Google PageRank, Alexa Rank, Compete Rank, Quantcast Rank), social bookmarks (del.icio.us, Technorati etc), subscribers (Bloglines, etc) Google ,Yahoo and Live Search backlinks and finally a whois and DNS report.

All 3 almost do the same, but differ by a little in the kind of data they retrieve, but they do give you a chance to know where all your blog has reached.