Google's DoubleClick publisher ad-serving platform crashed Wednesday morning with reports noting the downtime is likely costing global websites big bucks due to lost advertising revenue.

The issue cropped up on a Google forum just before 8 a.m. EST with users asking if other web site operators were experiencing issues, including a 502 bad gateway error and failing ads resulting in very slow page loads. One user noted ads were falling back to AdSense through DoubleClick for Publishers and were being served up correctly.

As of 10 a.m. there was no response from Google to the forum requests for information on the issue. A Twitter feed  regarding the issue also notes no response from Google as of 10:25 a.m. EST.

One news report stated sites impacted included BBC.com and the Wall Street Journal and noted lots of inquiries and reports on Twitter.

Google bought DoubleClick in March 2008 and launched DoubleClick for Publishers and DoubleClick for Publishers Small Business in 2010. It used to be called Google Dart.