A recent trend in the Japanese web advertising market may presage changes that could come to the Western world. As described here, some advertising in Japan now includes a picture of a filled-in browser search box instead of a domain name. The idea is that an advertiser can buy top-of-page advertising at the main search engines for various terms and then suggest to people reading their print ads to use those terms to search.
This strategy takes advantage of the simple fact that most people simply type into the search bar instead of the address bar. If you can control what they see on the first page of the search results, you have a good chance of getting them to your web site.
Of course, this strategy also has some huge downsides. First, you need to advertise on al the popular search sites for the duration of your "search for this" ads. Even if you do that, a canny competitor might buy ads for the same words in order to siphon off your viewers. Unless you are a huge advertiser, you cannot control the top of enough of the search engines to make this a sure-fire strategy. Sticking to good old domain names is safer, although it has the cost of knowing that people typically type them in the wrong place in their browsers.