This is the final of a four-part series on how to make the most of, and what to be wary about, search engine optimization.
There's a term for the practitioners of search engine optimization's dark arts: "black hat SEO."
The SEO industry is as known for its bad practitioners as it is for the genuine good it can do to help a site score better in rankings on Google and other search engines.
The good news is, the bad operators are over-hyped.
"The main problem that people run into isn't so much black hat techniques … as useless techniques," says Alhan Keser, the chief marketing officer at Blue Fountain Media, a New York-based digital marketing firm that specializes in SEO.
The bad news is that old tricks - keyword stuffing, link-swapping, writing junky articles - and unethical tricks are increasingly blending.
There are a few main thrusts to SEO: Optimizing a site for search engines; generating content to fill your Web pages and catch those search engines' attention; and drumming up links to your pages, to establish their credibility in the eyes of others.
There's nothing wrong with any of these ideas in and of themselves. What's critical is that they need to be achieved organically - consisting of real information, generated by real people, for the right reasons.
In looking for help with SEO, here are some warning signs to watch out for:
Link farming and link swapping:
Bad SEO is SEO that takes shortcuts. Where search engines want to get a picture of what online information is really valuable and useful, bad SEO tries to distort reality and fool search engines into making information seem more valuable than it really is.
Usually, it does this by using one of a few techniques to jam the Internet full of bogus information.
The most notorious and venerable (and yet still prevalent) among these are the link farmers. Search engines pay close attention to how many links point towards a web page, on the principle that a page that a lot of people link to is probably more relevant than a page few people do.
One of the oldest SEO tricks, then, is to create thickets of Web pages with lots and lots of links.
Often it's effectuated by outsourcing: a scammy local SEO provider will offer services to a client, only to turn around and send the work to an overseas network that will whip up phony links in a hurry - then vanish when the search engines catch on, leaving the client high and dry.
Be wary of any SEO providers who promise fast or guaranteed results, and SEOs that promise to add your site to their "blog networks" or to "directories" that you've never heard of and would probably never use. The only links worth having are from sites worth visiting.
Stuffing and spamming:
Also be wary of any SEO approach that looks like it's going to fill your site with junk in order to boost its rankings.
In years past, one popular trick was to fill a site's homepage with keywords, often in small print or invisible text, hoping that search engines would be impressed by the repetition. (If they were, they're not any more.)
More recently, the trend has been towards filling Web pages with not just spammy keywords, but pages and pages of low-value paragraphs, written on the cheap. (Not only was this an SEO technique, it was the backbone of businesses like eHow.com.)
As the Internet filled up with pages that looked legitimate but really weren't that helpful for most readers, search engines worked to weed out unhelpful long-form text as well. So any SEO strategy that involves cooking up text that's repetitive or not manifestly useful for readers is unlikely to go far.
Do some due diligence:
How to check the credibility of an SEO provider? There are some investigative tools at your disposal.
"The first thing I'd do is ask them for one of their clients," Mr. Keser says. Ask for a case study in which the SEO put a client on the first page of a Google search for a given search term - which, after all, is the goal of SEO. This provides the opportunity for some due diligence.
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