There are a lot of search engine marketing tools out there. And some are free, like my CombineWords.com keyword tool, and others are paid tools. Well, I have to admit that there are only a few search engine marketing tools that I actually use on a regular basis, one of them being SEMRush.com, from the makers of SEOQuake. Keyword Research is an essential part of search engine marketing, and the search engine optimization process. You absolutely have to start with the right keywords, and being able to do the proper research is key. So, here is my SEM Rush Review, a search engine marketing tool for keyword research that I just cannot live without.