Ten years ago, about 80 percent of people used a travel agent to make travel arrangements. The agents had a computer tied into the airlines and they shopped for a ticket for you. That started changing in 1999, when people began booking flights on their own. First airlines created their own Web sites. But these were pretty difficult to use, so people started the habit of using Travelocity, Expedia and other booking engines. Airlines then countered by making their sites easier to use. Today, it’s hard to say if any one site is the best because none of them will give you the best fare every time. Each one uses different architectures and shopping techniques. That’s why Clark likes Sidestep, an alternative to all of the “regulars” that searches deals alongside regular engines. In addition, more booking sites are coming on the market that are in “beta” stage but still work great. The first is Mobissimo. Clark has found it decent for domestic deals, although it takes a while to search. But it’s great at finding international travel deals. One launching next month is Kayak.com, and another good one is farechase.com.