1) SEMrush - I believe that among all the 3rd party software, SEMrush has the largest keyword database. Their search volume data is pretty accurate and aligns with the Google keyword planner. Also, based on the type of content that needs to be produced (i.e. informational, transactional, etc.), one can utilize different filtering options available in it.
Matthew, are you still using LTP as part of your strategy given the changes with Google AdWords and MOS the past few months. None of their training reflects these changes in the video tutorials, so it’s a bit slower on the learning curve and seems very limiting on some of the LT Keyword options that are registering no data, when we know there is search data for certain words. Seems like something that was designed to work incredibly smooth is playing catch up from changes in 2 major areas, MOZ and Google.
Bing Webmaster Toolbox: Oh yeah, remember that other search engine? Yes that’s right Bing has a whole collection of tools of their own, including keyword tools. The data will be taken from Bing itself, which means that you should be able to make relative assumptions about keyword popularity. because lets face it, Bing users aren’t that different than Google’s.
As for the history of the company, as I explained, I created Long Tail Pro back in 2011. At the time, I was creating tons of niche sites and was doing alot of keyword research and content creation. I was trying to figure out what types of keywords would rank quickly in the search engines, specifically Google, and I was frustrated with the other keyword research tools (in particular Market Samurai) out there.