The effects of the Google "This site may harm your computer" search bug may last longer than at first appeared.
The original problem - all search results came back flagged as potentially harmful, with Google refusing to link directly to the sites - cleared in around ten minutes, but on further investigation it appears that some valid incoming email to Gmail has been flagged as spam.
This email includes mailing lists and Google Alerts, and as of 15:59 GMT the mis-categorisation was still happening. Like the Google search problem, it appeared to start at around 15:00 GMT.
If you use Gmail, check your spam folder to see if recent incoming email has been incorrectly diverted.
UPDATE - There are rumours that the problem was caused by stopbadware.org, " a partnership among academic institutions, technology industry leaders, and volunteers, all of whom are committed to protecting Internet and computer users from the threats to privacy and security that are caused by bad software." who is a partner with Google. The site went down at the same time as the Google harm bug appeared.
However, the organisation denies that it's a cause, saying instead that it's a victim...
"This morning, an apparent glitch at Google caused every search listing to carry the "Warning! This site may harm your computer" message. Users who attempted to click through the results saw the "interstitial" warning page that mentions the possibility of badware and refers people to StopBadware.org for more information. This led to a denial of service of our website, as millions of Google users attempted to visit our site for more information. We are working now to bring the site back up. We are also awaiting word from Google about what happened to cause the false warning."
That went up around five minutes ago. Like them, I've got a query in with Google, which is currently staying very quiet on the matter.