I want to share how and why I sold the company in order to both educate and inspire potential software entrepreneurs.  I certainly don't know everything and obviously companies sell for much more than I sold Long Tail Pro for (I won't be featured in Tech Crunch anytime soon); however, I'm willing to share what I have learned and hopefully that can be beneficial to a few of you.

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.
This is one of the best articles on Keyword research tool that I have encountered. However, To add more to this, I just wanna point out a tool (LSI Graph) for an outstanding long tail & semantic keyword research. After the recent Google algorithm, Google is now, however focussing more on context & semantics than keyword alone. What do you think about it?

When I finally made the decision the get Long Tail Pro way back in December of 2012 – I honestly had no idea how much this one piece of software would impact everything I do online. I knew that it would help me find more and better keywords right off the bat. But I didn’t know exactly how much it would positively affect my ability to actually make money online. I can say with confidence, that Long Tail Pro is the one tool that has made the biggest difference (by far), in my ability to get traffic to websites and actually earn money online.

This keyword tool was built on a custom database we have compiled over the past four years. We researched data from the (now defunct) Google Search-Based Keyword Tool and also looked at a few more recent data snapshots to refresh the database and enhance our keyword coverage. Our database contains 28,527,279 keywords representing 13,762,942,253 monthly searches. Our database is primarily composed of English language keywords.
Basically, Google shows the autocomplete suggestions whenever you start typing anything into Google search box. It is in Google's best interest to show the most relevant keywords in the autocomplete suggestions. Keywords that would help Google to retrieve the most relevant websites and help users find the most relevant content for their search query.

Because great content requires a deep understanding of the main idea (e.g., “ac repair houston”) and the supporting subtopics that require coverage (e.g., “central ac vs portable ac systems”) and the common issues that users seek answers for (e.g., “freon,” “refrigeration loops,” “coolant refills,” “troubleshooting”), the effectiveness of a keyword reporting tool is only as strong as the SEO pro using it.
To be convinced of the effectiveness of the product, you have to watch the video. The major benefit you are going to derive from the product is the multiple seed keywords it delivers. Unlike other similar products that give only single seed keyword, you would get multiple seed keyword with this program and you can get this at a time. Because you can process more than one seed at one time, it saves you a lot of time and resources. This is a huge plus to this product.
From the review above there is no doubt on LongTailPro benefits. You can grow your business quicker by making sure that the LongTailPro is your partner. The price may be high, but you can avail trial by clicking on the link below and all you need to do is to purchase. The LongTailPro download option is not available anymore. Other LongTailPro alternatives in the market today claim to be cheaper, but they can’t deliver. Drive traffic and earn more with the use of the LongTailPro tool.
Once I have a list of phrases, rankings, and volumes from these tools, I'll look to internal tools (maybe Excel, Access, or another database) to organize, classify, and forecast opportunity. This is where I'll estimate a competitor's traffic based on volume & position CTR, set goals for a target position, and estimate traffic based off that position's CTR and keyword volume.

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).