There is a thread at WebmasterWorld and several in the Google Analytics Help forum with complaints that Google Analytics is no longer tracking Google AdWords data properly.
The WebmasterWorld thread has this complaint:
In two of my analytics accounts for sites which I use adwords to drive traffic all of the data is being recorded as direct and not google(cpc)...and it not reporting any traffic from adwords (which my wallet tells my otherwise!)It is only for the past two days including today. Is anyone else seeing this? Is it a glitch?
The simple answer is that in February, Google notified us that we need to link our analytics account to our AdWords accounts to pass this information. So if you have not done so, and your Analytics data is looking a bit empty, go ahead and link up those accounts. Brad has a good post explaining how to link up your accounts.
Forum discussion at WebmasterWorld and Google Analytics Help.