Dec 14, 15:57 EST
Resolved - The issue has been resolved and full service has been restored. Please contact Support at http://success.pardot.com if you encounter any further issues. We sincerely regret any inconvenience you have experienced as a result of this incident.
Dec 14, 15:24 EST
Investigating - The Salesforce Technology team is currently investigating a service disruption impacting a subset of Pardot accounts. During a service disruption, end users are unable to access the Pardot service. Updates will be posted here as new information becomes available.