To verify 7.7 million listings, as untold numbers are constantly dropping off and new ones are added in more than 220 countries, is a daunting task. By its nature, this will be an imperfect process.

Airbnb’s recent quarter was its most profitable ever and also the best in terms of revenue, according to a shareholder letter the company released Wednesday. Airbnb reported net income of $1.6 billion ...