Most of the large international airfreight carriers are on one of three online booking portals--Cargo Portal System, the recently sold Global Freight Exchange or Asia-focused EzyCargo--and many of those that aren't are finding it necessary to offer tools online that include online booking.
For much of the industry, booking is only part of the picture. The portals are keeping track of shipments beyond the booking and they're offering interactive tools that connect to carrier sites. It may not exactly be the Web-based check-in of the passenger world, but for freight shippers and forwarders, technology and shipping increasingly are part of the same picture.
Source: Air Cargo World, http://www.aircargoworld.com