There is an important change coming up for those Google AdWords users who use Google Analytics to track their campaigns. Brad posted this information yesterday, but just in case you missed it, here it is again.
This is the email being sent to those that are impacted by this change. But I am concerned that not everyone who would be impacted by the change received the email, so here it is:
On March 4th, we will be updating how Google Analytics imports AdWords data to improve security and provide greater control and convenience. This update will require that your AdWords and Analytics accounts are linked and that you have "Apply Cost Data" selected. We are proactively notifying Administrators of Analytics accounts that will be affected by this change (you either have auto-tagging enabled and/or have a linked account without cost data applied to some or all of your profiles).
If you are receiving AdWords traffic (e.g. Visits), but the AdWords reports in Google Analytics do not contain impression or click data (e.g. CPC, Impressions, ROI), then it is likely that AdWords and Analytics are not linked or the cost data option is turned off for that profile. The cost data import option is selected by default when linking your accounts; however, new profiles created after the linking process may not have cost data implemented.
There is a Google AdWords Help thread with additional instructions on how to link your accounts, if you need to take this action.
AdWordsPro Stephen explained that this change is being done for security reasons.
Forum discussion at Google AdWords Help.