Growing the keyword list. There are a wealth of sites that will help you define and expand your search terms; some have been around for years now, while other fresh faces are bringing new depth and features to the job of broadening the reach of your search marketing campaigns. What follows is an overly brief list of online tools to compare and contrast:

1. Adwords Keyword Selector Tool provides access to trended search volume, and potential SEM cost & position estimates<
2. KeyCompete shows PPC keywords by advertiser, nice competitive source with a flexible array of uasge & pricing options
3. SEO Book’s Keyword Suggestion Tool draws for a healthy range of data sources
4. Trellian’s Keyword Discovery looks mighty cool, check out this detailed review at ClckZ
5. WordTracker now features more options [unlimited projects, UK keywords] and a more usable interface.
6. WordZe is new and looks sharp. Keyword-based search and link trending. Will explore shortly.
7. Yahoo Search Marketing’s Keyword Tool looks like it produces the same results as the classic Overture Keyword Selector. I was hoping to see a difference in results with the fresher flavor, but so far it looks like the interface and adgroup integration are what the new version has going for it.

Got more? I’m all ears.