Hits, Page Views, Unique Visitors
What is a hit? In web analytics, a hit is any request for a file from a web server. By request means a hit calculates page content delivered, all images to complete that page, and any additional files that need to be loaded to make the web page you are looking at, appear the way it does.
What is a page view? A page view is a request to load a single page of an internet site that results from a page request from a web surfer clicking on a link on another HTML page which is pointing to the page in question.
What is a unique visitor? A unique visitor is access from a single IP to a web server that generates page views and hits during a particular visit. When a visitor has cookies disabled, there is no way of establishing if they are a unique visitor or not.
Activemeter, Sitemeter, Statcounter, wordpress stats and all the others will never agree. Each one of them decides how and what they will count as a hit. Some count page views and some count unique visitors. Therefore, use any of the stats counters only as a general guide to hits.
Understand that an application that is not running on the same servers your blog is on is going to be susceptible to wild fluctuations. This is because all hits have to be transferred over the internet to different servers, and there are literally thousands of things that can go wrong between the server your blog is on and the server at the stats place.
Also be aware of the possibility that the software or hardware at the stats place may be broken and not recording, or counting things as intended.