Google mistook its own Custom Search Blog for spam and deleted it this week, after which it was hijacked by someone unaffiliated with the company.

The change was first noticed by the Google Blogoscoped website, which noticed that posts on the Custom Search Blog had been deleted and replaced by a strange comment from someone identifying himself as Srikanth.

"Google Custom Search, is the wonderful product from Google which many webmasters have been looking and dream for," Srikanth wrote. "Also Google Custom Search is integrated with Ad-sense, which means make money while keeping users on your site for longer time with custom search engine.... Good Luck for all the Custom Search customers(??)."

This blog typically offers tips and tricks for users of Google's Custom Search Engine software, which can be used to build custom search pages.

Srikanth's tone was obviously out of character for an official Google blog, prompting Google Blogoscoped to speculate that the site may have been hacked.

The answer turned out to be less sinister, according to Sean Carlson, a Google spokesman.

"Blogger's spam classifier misidentified the Custom Search Blog as spam," he said via email. Typically Google notifies blog owners when it has spotted content associated with spam on their websites to give them a chance to clear up any misunderstandings.

However, that didn't work out in this case. "The Custom Search Blog bloggers overlooked their notification, and after a period of time passed, the blog was disabled."

When blogs are disabled like this, their URL becomes available to the general public. That's when Srikanth swooped in and wrote the joke post.

"It was a case of "URL squatting" and not a security issue or any kind of hack," Carlson said.

Google quickly realised its mistake and the Custom Search Blog is now back in action.