Not too long ago I reviewed a site for a client and discovered that all of their PPC campaign traffic was landing on 404 pages. It was happening because the links used in their PPC ads were broken. Their campaign was setup by another consultant who does PPC work. During the process, the consultant had created custom tracking URLs for the campaigns but somehow had forgotten to use ampersands to separate parameters! Instead of a properly formed URL like this:
Their URLs were all formatted like this:
This oversight broke every single link and each PAID visit landed on a 404 page. This was true across hundreds of ads and thousands of keywords and wasted a ton of my client’s money.
The moral of the story: test your URLs!