Thousands of people got an email from Airbnb a couple of weeks ago, and they made maybe a $15,000 mistake. At least one man did according to an article by NPR. Airbnb went through its initial public offering, and its stock price more than doubled almost instantly. Now, tons of Airbnb hosts who had received an email a couple of weeks ago offering them a chance to buy stock ahead of the IPO are kicking themselves for missing out and missing the email.