Keywords are the core of Search Engine Optimization (SEO) for any site. Actually, keywords should be a major part of any online marketing program including social media campaigns, e-mail campaigns and online advertising. There are many tools available to research which keywords and keyword phrases are going to work for you, and to track your rankings over time.

Free Keyword Tools

All the major search engines make suggestions as you type in their search boxes. Start typing in your main keywords to see what other related keywords the engines are suggesting. This is a good place to start.

Clusty is an niche engine that provides a nice cluster of related keyword. Soolve aggregates the suggest features of numerous engines, so it is a one-stop shop. And Quintura shows a fun tag-cloud type result.

Both KeywordDiscovery and WordTracker have long been important keyword tools. They have free versions, but the paid versions are the real thing. WordStream recently released a free tool as well.

Google Insight for Search is a newer tool where you can compare keyword search volume patterns across specific regions, categories, time frames and properties. and Microsoft’s Keyword Forecast does much the same.

You don’t need an Adwords account to use the Google Adwords External Keyword Tool or the Google Traffic Estimator to find great suggestions and data on keyword performance.

And don’t forget to leverage your analytics package to understand past keyword performance.

Paid For Keyword Tools

While not directly a keyword tool, running Google Adwords PPC campaigns may be the best long term tool for understanding which keywords are going to work for you. Adwords can be used for amazing market research with relatively little investment.

• Rank Tracker has some nice rank tracking features and reporting.
• Market Samurai includes a number of SEO tools. I really like the SEO Competition and Keyword Research modules.
• Web CEO has a lot of features, but I haven’t tried it yet.
• Internet Business Promoter (IBP) is well regarded if a bit complex. Its link building tools are very good.

Subscription SEO Websites

The subscription websites offer tools, guides, forums, videos and other helpful materials

• Rand Fishkin’s SEOMoz includes a suite of tools, some of which are free. Pro memberships start at $80 per month.
• Aaron Wall’s SEO Book is well known for a great forum and training and lots of tools, many of which are free. Membership is $300 per month.
• Raven SEO has a sweet of hosted tools, including a Social Media Monitor, starting at $80 per month.

This is not an exhaustive list of tools or providers. If you have any suggestions please leave a comment.

Damon Horowitz of Aardvark, a social search engine, who is both a computer scientist specializing in artificial intelligence and a professor of philosophy, makes the case that AI shouldn’t be about simulating human intelligence, but should be facilitating human interactions.

I contributed a guest blog post at the Minnesota chapter of the American Marketing Association (AMA) website. My topic is a high-level approach to building content and links for search engine optimization (SEO). Here is an excerpt:

I was throwing around tips and tricks with some SEO pros the other day when the conversation lulled. One of the old hands, a self described reformed black-hat search engine optimizer, remarked wistfully, “When it comes down to it the only thing that matters over the long haul is content and links.” After some smiles and nods from his audience he continued, “You can try all the tricks and schemes, but Google eventually catches on and changes the game and then you’re back to what works anyway.”