Apologies if it's been covered, if not here ya go:
Dear AdWords Advertiser,
We're writing to remind you about a change to Google's advertising policies we announced in our Policy Change Log that may affect your AdWords account: https://support.google.com/adwordspolicy/answer/4271759
Beginning in the coming weeks, we'll no longer accept ads that promote graphic depictions of sexual acts including, but not limited to, hardcore pornography; graphic sexual acts including sex acts such as masturbation; genital, anal, and oral sexual activity.
When we make this change, Google will disapprove all ads and sites that are identified as being in violation of our revised policy. Our system identified your account as potentially affected by this policy change. We ask that you make any necessary changes to your ads and sites to comply so that your campaigns can continue to run.
Sincerely,
The Google AdWords Team
You've received this mandatory email service announcement to update you about important changes to your AdWords account.
The trend isn't particularly surprising, but hitting it this hard & this suddenly is sorta. Discuss if you wish...