PC World


It's bound to happen: AltaVista has a link to exactly the Web site you're looking for. But you're searching at Google, which doesn't know that particular site from Adam.com. Enter metasearch engines (also called metacrawlers). Instead of maintaining their own Web indexes, these sites call on other engines and directories each time you issue a query. Most metasearchers combine results, weed out duplicates, and present you with more links than you'd get if you confined your search to a single engine.

In the early days of the Web when no single search engine had indexed more than a few million pages, metasearchers were essential. Now AltaVista, Google, and other engines boast indexes of hundreds of millions of pages and let you comb a significant percentage of the Web all by themselves. Still, the best metasearch engines are worth trying, especially at times when your favorite single-engine search site strikes out. Unfortunately, metasearchers often fail to match the relevance of Google--probably because it's so tough to mesh links from disparate sites coherently.

Today, the Web has numerous metasearcher sites. Among the most prominent are Dogpile, Mamma.com, MetaCrawler, ProFusion, Search.com, and TheBigHub.com. Each one melds results from a lineup of search sites: MetaCrawler, for example, draws from 13 engines--among them AltaVista, Excite, Google, and LookSmart--while TheBigHub.com relies on only eight. But the more engines a metasearcher queries, the longer your search can take. Each time you issue a query, the metasearcher must pass it to the other sites, retrieve the results, and fold them into a single list. By reducing the number of engines it uses, a metacrawler can keep response times to a reasonable length.

The popularity of metasearchers has encouraged many traditional engines to acquire metasearch-like features. Ask Jeeves, for instance, provides results from About.com, AltaVista, Excite, WebCrawler, and 4anything Network in addition to the results from its own database.

Searching for the Best

MetaCrawler, our favorite metasearcher, draws on solid search sites such as AltaVista and Google, which helps it bring back plentiful and pertinent results. It trolls through all sorts of Net resources, too. Search for Beethoven and you can click on tabs to leap between engine and directory results, MP3 music files, images, newsgroup discussions, and even online auctions relating to the great composer and his music.

Another worthwhile metasearch site is Search.com, largely because of its specialized metasearchers on dozens of topics. The Automotive one, for instance, queries Autobytel, Car and Driver, CarPrices.com, and nine other car sites. But Search.com's general-purpose metasearcher often starts by returning a link from GoTo.com, a search engine that invites sites to pay for higher placement in its results. When we searched for Dell Computer at Search.com, it referred us to GoTo's paid link to a company that leases Dell PCs before it identified Dell's own home page. But at least Dell's site was the second link at Search.com; at Mamma.com, it was number 18.

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