Facebook headhunts new chief security officer Alex Stamos from Yahoo

Status update: Cheerio Yahoo, I've found a new job at Facebook

Social media giant Facebook has appointed a new chief security officer, Alex Stamos, headhunted from rival Yahoo - and starting this Monday.

The new hire was revealed, predictably enough, in a posting by Stamos on his own Facebook page, as well as a Tweet late last night.

"I am excited to join Facebook as their CSO next Monday. Thank you to the Yahoo Paranoids and best wishes," he wrote. The move comes just over a year after taking the role of vice president of information security and CISO at Yahoo - a move he made in March 2014.

In his Facebook posting, Stamos praised the Yahoo security team that leaves behind.

"The internet has been an incredible force for connecting the world and giving individuals access to personal, educational and economic opportunities that are unprecedented in human history," Stamos wrote on Facebook. "These benefits are not without risk, and it is the responsibility of our industry to build the safest, most trustworthy products possible."

"This is why I am joining Facebook," he added. "There is no company in the world that is better positioned to tackle the challenges faced not only by today's Internet users but for the remaining two-thirds of humanity we have yet to connect."

Stamos joins Facebook after its previous CSO, Joe Sullivan, left in April to join taxi company Uber.

At Yahoo under CEO Marissa Mayer, Stamos will have been responsible for many of the improvements in security at the company, particularly the use of encryption for Yahoo Mail, or Ymail, after the Edward Snowden disclosures revealed just how much snooping the US National Security Agency and GCHQ - and, no doubt, other intelligence services - do on insufficiently secured communications.

Stamos had also been one of the people behind TrustyCon, an event organised to rival the RSA Security Conference in 2014 in protest at RSA's admission that it accepted $10 million from the NSA to use a weak number generating algorithm by default in its BSafe toolkits.

Before Yahoo, Stamos had been chief technology officer at Artemis and had co-founded iSEC Partners, a security testing and consulting organisation.

However, many might feel that he left an unfinished job behind at Yahoo. Responding to his tweet, Trevor Timm (@trevortimm) wrote: "Congrats! Can you flip the switch on HTTPS-by-default for Yahoo News before you leave". Nima Fatemi (@mrphs) added that he ought to do the same for Tumblr blogs, too.