As you can see, LongTailPro is pulling data from Google Adwords. WHAT?! So LTP uses a mix of their own massive data (launched in 2011) and data pulled via API from,, and Google Adwords ( Once you input your seed keywords, LongTailPro outputs suggested keywords related to your seed keywords, search volume, Adwords suggested bid, Adwords competition, total words, rank value, average keyword competition, language searched, and location searched.

WordStream's Negative Keyword Tool reduces wasteful PPC spending and improves ROI by preventing your AdWords PPC ads from showing on irrelevant searches. Enter a keyword to get a list of negative keyword suggestions. Then select the ones that aren't relevant to your campaigns and export the results for use in your AdWords account. As a result, your ads will be more relevant to searchers, grab a much more targeted audience and reduce your overall ad spend.
Google has introduced Google Suggest in 2012. Google Suggest is typically used as a live feature while a user is typing a search phrase into the browser or google website. Google Suggest uses the organic search input of billions of users and try to "guess" that way what a user might be searching for even before he completed entering the query or all the words of a keyword phrase.
The limit on manual keywords could be higher.  I personally wish we could input 10,000 keywords at a time, instead of 200.  However, I understand the costs that Long Tail Pro has to maintain each time a new manual keyword is input.  Not a deal breaker, I just wish the limit was higher. (To be fair, I don't think most keyword tools have a bulk manual option at all).