Most keyowrd databases consist of a small sample of the overall search universe. This means keyword databases tend to skew more toward commercial terms and the core/head industry terms, with slighlty less coverage of the midtail terms. Many rarely searched for longtail terms are not covered due to database size limitations & lack of commercial data around those terms. Plus if those terms were covered, there would be large sampling errors. Google generates over 2 trillion searches per year and claims 15% of their searches are unique. This means they generate searches for over 300 billion unique keywords each year. The good news about limited tail coverage is it means most any keyword we return data on is a keyword with some commercial value to it. And with Google's Rankbrain algorithm, if you rank well on core industry terms then your pages will often tend to rank well for other related tail keywords.

We’re not here to dwell on the good and the bad of Google’s decision. I personally am elated that this debate has brought the crucial SEO function of Keyword Research into the limelight once again. There’s more to it than taking the first 10 results from the Google Keyword Tool and scattering them left, right and center in your content. Savvy keyword research is what separates strategists from headless chickens.
Wordtracker is another service that requires an annual subscription to utilize all of its features. Their database is made up of 330 million search terms, collected from the major metacrawlers, Dogpile and Metacrawler, and is updated weekly. The search data they show is a record of the number of times the exact keyword or phrase has been searched in the United States over the last 365 days. As in the case of Keyword Discovery, this difference in default keyword matching type causes Wordtracker to display search volumes significantly lower than what Google’s tools show.

Hey Alex – this is a good question. No tool is going to be spot on. My advice is to not look too much into the accuracy of the metrics, but look at it more as a relative measure. I’m finding Ahrefs to be a good barometer for keyword competitiveness, but I’ve also heard great things about KW Finder lately. I think it’ll more come to personal preference. Both are solid options.
But it’s still very useful for getting search volume data (provided your account still shows this), which is helpful when choosing which of the many keywords you’ve found to focus on (although you should take these estimates with a pinch of salt, they are still useful in indicating the relative search volumes of different keywords, even if the absolute estimates are a little off).

I would like to get LTP but I’ve read that people have some issues according to Keyword Planner and Moz. Do you still recommend this tool? How accurate is it’s data comparing to previous versions? Does Keyword difficulty still works as it should? Maybe it’s better to wait untill some stability of this software? I don’t want to waste money for some tool which doesn’t work properly.

If you go to Search Console under the Acquisition tab and then click Queries, you’ll be able to see different searches (aka keywords) that users found you through. You may have to set this up, but it’s easy to do and only takes a few minutes; you can see how here. Use this information to evaluate and monitor your keywords to see what’s working and what needs to be changed.
Once you've entered a keyword, you'll be presented with a range of data: Google Search Volume, Competition, CPC, and Opportunity Score. This data provides advertisers with at-a-glance data that they can use as the basis for their next campaign. No other free keyword tool provides as much free keyword data as WordStream's new and improved Free Keyword Tool. Try it today and see how much easier keyword research can be with WordStream.

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.