We have surveyed the availability of the official websites of US presidential candidates Barack Obama, Hillary Clinton, John McCain and Ron Paul from February 15 to April 7 (using Uptrend's uptime monitoring service). These websites are an important medium for the candidates, where press releases and information about the candidates can be presented, and it is therefore critical that these websites are stable and always available on the internet.

Barack Obama’s website suffered no outages during the monitored time period, and neither did John McCain’s. Ron Paul’s website was only unavailable for a mere five minutes. In contrast, Hillary Clinton’s website was unavailable for a total of 29 hours and 50 minutes. The majority of that time came during four days in March.

Hillary Clinton’s website suffered from frequent loading problems during the period of March 20-23. The problems started 3 p.m. EST on March 20, and didn’t stop until 5:30 p.m. EST on March 23. During this time, the website was unavailable for a total of more than 27 hours. There was no single long outage, but a continuous series of shorter intervals where the website simply did not respond. As many as 40% of all requests to the website failed during this period.

The reason for the problem is unclear. The website could be reached, but did not respond. This could be due to the website being overloaded by an excessive amount of visitor traffic, or some other internal performance problem.

It is very unusual to see this extent of downtime for such a high-profile website. The problems started soon after the US National Archives released the 11,000 pages of records that detailed Hillary Clinton’s time as a first lady, but this may be a coincidence.