That particular hack dated back to 2013, but last week's revelation came just a few months after another high-profile Yahoo email hack was uncovered, this one affecting 500 million accounts. Throw into the mix controversy surrounding Yahoo's reported complicity in helping U.S. authorities scan customer emails, and you'd perhaps be correct to question anyone who continues to use Yahoo to send and receive emails. But one company's loss is another's gain, and Swiss email startup ProtonMail says it has seen an uptick in visitors since the second Yahoo hack was exposed, with a notable rise emanating from one country in particular. "After Yahoo, new user growth doubled, but a huge surge is coming from Germany after the German government took the unprecedented step of advising German citizens to stop using Yahoo Mail," ProtonMail cofounder Andy Yen said in an email to VentureBeat.