Hackers targeted SendGrid, a mass email service used by 180,000 companies including Uber, Pinterest, Spotify and Foursquare. SendGrid sends transactional emails on behalf of trusted companies like Spotify and Pinterest. The attack follows a similar pattern to an attack last year against a former SendGrid customer. There is evidence that other Bitcoin companies are being targeted via their mass email providers, including Mailchimp, Localbitcoins and Btcjam. The attacks were unsuccessful because both clients used two-factor authentication.”]