The so-called homesharing economy continues to heat up. Expedia Group said it had acquired two small startups — Pillow and ApartmentJet — which help owners of multifamily residential communities list and manage short-term rentals while complying with local regulations. Pillow, a San Francisco-based startup, had raised $16 million in capital, including a $13.5 million Series A round last year led by venture capital firm Mayfield. ApartmentJet, a Chicago startup, had disclosed $1.2 million in funding, with Network Ventures and BlueTree as key backers. Pillow offers online tools that enable multifamily building owners to access information about short-term rental guests and monitor which tenants are renting out which of their units. The company also helps resident hosts to comply with regulations, licenses, and taxes.