Location-based services use location and time data to provide services through mobile devices. Booking aggregators display results from multiple online travel agents (OTAs) and generate revenue from advertising and referral fees. Specialty portals contain customized resources for specific fields. OTAs offer planning and booking capabilities for travel. Last-minute booking apps provide discounted offers close to travel dates. Channel management allows changing rates across booking platforms. Direct bookings are made on hotel/airline websites without third parties.