Full service has been restored as of 12:16 UTC. Customers on the impacted database shard now have access to all Pardot services. As part of our standard process, we are performing a full root cause analysis and will provide our customers with the details once they are available. We understand the impact this has had on our affected customers and extend our apologies. Please contact our Support Team at http://help.pardot.com
if you encounter any further issues.