When it comes to marketing, search engine optimization, or SEO, is probably the most mysterious undertaking of them all. And yet, it's one of the most important things you need to get online visibility.

The challenge with SEO is that search engines--like the almighty Google--make adjustments to their algorithms all the time. A shining example is the Penguin update late last year, which had marketing folks everywhere clutching their pearls. These algorithms determine how high you rank naturally on a search engine results page, or SERP, when someone types in a search term. They're based on lots of constantly changing factors that are more heavily guarded than the crown jewels.

Big companies hire big agencies to make sure their sites are fully optimized, but if you're a small business, the last thing you need to do is learn the ins and outs of SEO. And it can get pretty expensive to hire someone, especially if you post content on a regular basis. (Tip: Creating useful, original content is one of the few tried-and-true strategies for SEO.)

But have no fear, cool tools are here! Check out these three optimization-software companies that help take the mystery out of SEO and get your site on its way to ranking higher in Google.

BoostSuite

BoostSuite is an awesome tool designed specifically for small businesses. It takes data from your website and turns it into a list of easy SEO to-dos. It even has a cool revenue tracker that shows you how much more money you could be raking in (in terms of qualified leads and eventually customers) if you make the suggested changes. Cost: Starts at free

Scribe

Brought to us by the awesome folks at Copyblogger, Scribe lets you optimize your content, social and search, with one tool. It tells you which topics are the most interesting and searched that are related to your industry, so you can create content that resonates. Layer on top of that tips to tweak your content for search and to increase social-media sharing, and you've got a pretty powerful tool. Cost: Starts at $97 a month

SEOmoz

SEOmoz is like the granddaddy of SEO best practices. The pro version helps you manage your SEO, analyzes your site regularly, and provides recommendations. You can also download a free toolbar that shows you SEO metrics of various sites as you surf online. But what I really love are the guides (like this beginner's guide to SEO) and help forum. Cost: Pro version starts at $99 a month

One last note on SEO: Don't cheat, such as using link schemes, stuffing your content with keywords, hiding text or links, or employing any other below-the-board tactics. You could get punished hard, and once you're on Google's crap list, it won't be easy getting off.

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