You have to setup some code in your blog, that code you will get from g.analytic and you can check any time how many visitors your site have from google, from direct visits etc.
You will find detailed explanation here:
Google Analytics Installation Guide - Analytics Help

When you setup an account with Google Analytics | Official Website they will give you

tracking code for your site, after you add that code to your site you'll able to

see your traffic report.

The benefit? Well without these reports there is no room for improvement for your

site, it's like shooting without the target.

Jamian

Google Analytics is a free service offered by Google that generates detailed statistics about the visitors to a website. Its main highlight is that the product is aimed at marketers as opposed to webmasters and technologists from which the industry of web analytics originally grew. It is the most widely used website statistics service, currently in use at around 57% of the 10,000 most popular websites.