I recently came across an issue with my Google Analytics website tracking whereby other websites had (probably accidentally) installed my tracking code (in the format UA-XXXXXXXX-X). This meant I could see visitor statistics for other sites in my profile, giving a false impression of a greater number of visitors to Web Dev Door.
There are a number of reasons why your Analytics tracking code may be used on other websites:
To setup a filter so only visits to your website are recorded in Google Analytics is straight forward. These steps use the new admin panel introduced in August 2013.
Entering your website domain without the ‘www’ in the hostname text box will mean traffic to any sub domain on your site along with the www will also be included in your Analytics.
Preventing Analytics referral spam and fake visits »