Many of you will have noticed that the site was unavailable for the last 3 hours. This was due to a security compromise of the software that serves the banner at the top right of the site. The result was that an invisible frame was loaded by a third party web site. This has been patched and I apologise for any inconvenience caused. If you have any security concerns then I advise you to run a scan of your computer for malware using a free scanner, such as this one offered by Sophos: Free Security Scans - Scan your computer or network for viruses, spyware, adware and other threats