Use the "regular expression" Retargeting Audience method to add people to an audience when the URL they visit matches a regular expression. This method is similar to the "Path" method but more complex, requiring knowledge of regular expressions. While "path" Audiences work great for 90% of use cases, like Querystring retargeting lists, sometimes you just need to use a regular expression (or "regex").
Scenario: Your company blog is located at "http://blog.constantcontact.com". You want to add people who visit the blog to a special Audience, but since the URL uses a subdomain rather than a subdirectory, you can't use the "path" method.
Solution: Create an "regular expression" Audience with target text of "blog\.constantcontact\.com". If the tracking tag is included on the site, when people visit it, they will be added to this new Audience.
Important: While we provide extensive support over e-mail for all aspects of Lead Gen & CRM Ads, we cannot teach you how to write regular expressions. If you need help with that, click here for a 3rd party tutorial.