Microsoft Corp.’s unsolicited, $44.6 billion bid for Yahoo! on February 1 comes at a strategic crossroads for both companies. Each must urgently adjust aging technologies and business models that are losing ground to Web services trends that their common competitor Google has effectively exploited.

The potential impact of any merger is measured by market share. And the yardstick in this one — Yahoo! rebuffed the offer before exploring a tie-up with News Corp. — is percentage of the Internet search market. Google, founded in 1998 and publicly listed since 2004, has a runaway lead, at 58 percent, according to online monitoring company ComScore. Yahoo! follows at 23 percent, trailed by Microsoft at 10 percent. Time Warner’s AOL and IAC/InterActiveCorp.’s Ask.com own nearly all the rest.

But just as there is more to these media-and-technology titans than search engines and the advertising and transaction revenues they generate, there is more to the search business than the consumer choices reflected in those shares. The keyword-search function that first popularized the Web in the form of the 1990s-vintage Netscape browser, which was ultimately absorbed by AOL, is powerful enough to return millions of responses to a given query. That, however, isn’t particularly useful to corporate strategists seeking specific business intelligence or to securities researchers trying to stay on top of market-moving developments at companies they cover.....