Google sent an email to many publishers yesterday, including myself, explaining a reporting issue with Google mixing up some of the earnings for link units with regular ad units. The email’s subject line read, “Update to AdSense link unit reporting” and the email read:

As a publisher using link units on your pages, we’re writing to let you know about a recently resolved reporting issue that affected your account.

We discovered an issue with the way earnings from link units were being shown in publisher accounts, which resulted in some of your ad unit earnings being incorrectly attributed to link units instead. However, this was only a reporting display issue and so your overall earnings and payments were not affected. We’ve resolved the issue, and as a result, you may now notice slight differences when you look at reports for previous months. Specifically, when you generate separate reports for link units and ad units, you may see that earnings from link units on a particular day have decreased, but that the ad unit earnings for the same day have increased by the same amount.

Again, please be assured that your aggregate earnings and payments were unaffected, so you’ve been credited for all valid clicks and impressions. In addition, this issue has not affected your ad performance in any way.

Your reports will now accurately reflect your earnings from link units and ad units — we apologize for the inconvenience and any confusion caused.

So no damage was done on the earnings side. Some publishers who may have looked closely at their reports to make tweaks to their pages may be suffering a bit, but overall, this doesn’t seem like a major deal.

AdSenseAdvisor in a WebmasterWorld thread added a bit to it:

Forum discussion at WebmasterWorld and DigitalPoint Forums.