This is another free tool for keyword research. The tool allows you to combine your keywords in a very easy manner. It has three main match types which include broad match, phrase match and the exact match. You can choose on any of them depending on your keyword search objectives. In addition, you can either use broad modifier or optional keyword or both. Most users are finding it to be a very useful tool in their search for the most appropriate keywords.
Long Tail Pro is a keyword research tool that helps you quickly find low competition keywords for your website. In particular, the tool is built for people doing SEO (search engine optimization) as opposed to people doing paid ads (Google Adwords PPC). I'm sure there are some advertisers that use the tool for paid ad keyword research, but the tool was built for SEO keyword research.