Since Google was founded as an Internet search tool in 1998, it has been evolving. How to best search the Internet continues to evolve as well.

Just as Google as the Internet's most popular search site earns a pile of money by directing you to sites that it tries to make as relevant as possible to your search objectives, others make money by having Google direct you to their sites, sometimes legitimately, sometimes not.

Both you and Google want you to avoid the illegitimate attempts.

Search engine optimization (SEO) is a legitimate endeavor that has evolved into an industry in itself. By coding their sites in specific ways and using other techniques, Webmasters by themselves or with the help of SEO consultants try to get Google to list their site as high as possible in its results when people do Google searches.

Link farms, content farms, article spinning, and keyword stuffing are among the illegitimate endeavors, falling under the general category of Web spam (also called search engine spam, search spam, and spamdexing), to try to trick Google into directing you to sites that may meet your search needs or more likely are junk that at best waste your time. Both you and Google want to avoid getting tricked.

Whenever you wind up at a site that's just a collection of links to other sites, that's a link farm. Whenever you land at a site, article, or blog post that seems to have been written by a machine, that's a duplicate or near duplicate of what you've already seen, or that seems to have been put together with the least amount of effort possible, you're at a content farm.

Article spinning is the manual or computerized rewriting of Web content, with or without the creator's consent, merely to enable it to appear at multiple sites and look slightly different. Keyword stuffing is the inclusion in Web pages of unrelated or repeated words or phrases merely to try to improve search results.

Google wages constant war with those employing these and related techniques, tweaking its search algorithms to try to avoid displaying such sites as part of its results. Matt Cutts, Google's "Principal Engineer" and the head of its "webspam team," has a blog in which he posts about these and other Google efforts, at www.mattcutts.com/blog.

But effective Web searching requires that you not just rely on Google even if you use Google as your primary or sole Internet search tool. Smart searching necessitates more than typing a word or phrase into Google's main search field.

Most people know basic search tricks, such as placing quotation marks around a full name or phrase when you want Google to treat it as a unit rather than separate words. This and other techniques become more easily accessible when you click on "Advanced search."

The second option there, "this exact wording or phrase," duplicates the quotation mark trick without needing quotation marks. You can also use this trick to avoid Google's normally helpful synonyms, directing Google to return only pages with the exact word you want.

Another basic but useful technique in narrowing search results is to type as many words are you think are relevant in the "all these words" field. If you get no or too few results, begin eliminating one word at a time.

The option to "Search within a site or domain" can be useful if you only want results back from sites with educational domain names, in which case you type in .edu. This can eliminate sites that want only to sell you something, but keep in mind that not all sites with .com domains are commercial.

Experimenting with Google's other options on its Advanced search page can only help you become a better searcher. But Google's home search page, for basic search, offers tricks of its own, which can take Google beyond a simple search tool. You can also use these tricks in the Advanced search page's "all these words" field.

Find the definition of a word or phrase by typing define: in front of it.

Type weather or time in front of a larger city; city, state, or city, country in front of smaller cities; or ZIP code for the current weather and forecast or the current time.

Convert units of measurement or currencies by typing, for instance, 10 km in miles or 100 euro in $.

To see which other sites link to a site, including your own, type link: in front its address.