Importance:
AWA
AdWordsAdvisor explains how Google monitors the CTR of keywords across multiple campaigns.
AdWordsAdvisor Says: [
Link to quote]
This is a good topic that is worth some clarification.
Essentially, the automated monitor that checks on the performance of keywords counts the impressions, clicks, and CTR for a given keyword in every place it occurs within an account.
For example, let's consider the keyword 'slightly twisted widgets' which occurs in 4 different campaigns in a hypothetical account. If the combined total of impressions is over 1000, and the combined total CTR is under the minimum standard, then the keyword will be disabled in all four places.
Hopefully this will make sense if you consider that it is in fact just one keyword.
When this occurs, it is important to delete the keyword in all places in which it appears before trying to re-enable it. If this is not done, and you re-use the keyword, it will be disabled again very quickly.
On a related point, it is a wise practice to delete disabled keywords as a matter of routine, regardless of whether you intend to re-use them or not.
