Predicting what users are typing is a very nice feature that is going to make your website visitors’ life easier. A typical example is the travel websites, more precisely Yahoo! Travel. As users type the departure city name the system shows possible matches.

This is a good example of how usability can have an economic impact, as predicting input will probably avoid a lot of errors. Imagine misspelled city names or unhappy users if your system does not identify a destination airport after clicking on the search button.

Other travel websites, like Expedia, Travelocity and Orbitz, are not taking advantage of this easy to implement feature. Bad for them.