Well there's no way you can accidentally type that out, so it's most likely from an ad or a deliberate phishing attempt. Some people may be too lazy in typing out the full address, so they search for the exchange in Google and go for the first result, which could be a sponsored ad. Deliberate phishing attempts come from emails or messages that look like they legitimately come from the site, asking you to click a seemingly legit link to drop your guard.

The best way to not get duped into these is to type the addresses out yourself, and maybe bookmark them if you're absolutely sure your computer is clean.