Keyword Tools Part 2

As a second installment of last "Keyword Tools" post, here are some additional free and subscription based keyword tools worth checking out:

SUBSCRIPTIONS:
SpyFu, KeywordSpy and KeyCompete offer similar services that allow you to "spy" on your competitors to find out what keywords they are buying. As with most of these scraping tools, the data is not 100% accurate and can be several months old -- but it's worth test drive.

I've subscribed to SpyFu for about a year but am switching over to KeywordSpy because they seem to update more often and as a whole is less clunky.

KeywordDiscovery from Trellian: Similar to WordTracker, KeywordDiscovery shows you which keywords generate the most traffic by gathering keyword search stats from more than 180 search engines worldwide. Features also include Spelling Mistake Research, Seasonal Search Trends and more.

FREE:
Clusty from Vivisimo: Clusty is a meta search engine that organizes search results into groups called "clusters". The benefit of using Clusty as a keyword tool is that it refines search results for a general keywords into more specific themes by sub-categories, which helps in building out keyword lists.

Google Suggest: Find frequently searched phrases based on the letters or words (even part of a word) in your query.

Yahoo Search Assist: Similar to Google Suggest, Search Assist expands on a search query to suggest additional relevant keywords. The main difference between the two is that Search Assist offers related topics as well as specific keywords as you type. I use both tools, however do think Search Assist is stronger because it shows results that include your keyword anywhere in the query, while Google Suggest displays only those terms that begin with your keyword.