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.
1) Google Keyword Planner: This tools is fantastic because it can help me to identify long tail keywords for my niche. It is official Google’s tool and it has the recent trends and keyword variations. For example you may think that this keyword is great “buy ipad air in liverpool” but Google may suggest “iPad air sale Liverpool”. Yes, not often it is accurate but when I’m using it alongside the other tools – I can get clear idea.
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.
I actually don't use any keyword tools aside from Google Trends, but only rarely do I even use that. I try to talk to many of our target audience members (entrepreneurs) as I can. I attend events, I have phone calls, I sit next to them while working. Generally speaking, I think it's a waste of time to START with keyword tools instead of actual customers. Yes, you can target people in broad swaths and get a high level sense for what's interesting and trending, but at least in the case of our business at NextView Ventures, it's way more powerful to talk to actual "customers" you serve.
As you might imagine, the ability to completely see and study how the competition is ranking for certain keyword phrases in your niche has significant value for any company. Tack this on with its other features, and Long Tail Pro makes a ton of sense for content marketers. And like I said before, the price tag is very low compared to some of the tools I’ve seen out there, with a one-time fee (NOT a monthly fee) of $97 and a 60-day, money-back guarantee.
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.