No doubt the long-term outlook of this product has changed dramatically since its initial conception and the 2011 acquisition. It's an analysis and recommendation engine built on search data for each site. That data used to be directly available to and collected by HitTail, since search terms were in the referring URLs of every visit to the site coming from a search engine.
Now that Google virtually never includes search terms in referring URLs, the only way HitTail can get the data it needs is via Google's APIs. Google can change the API, remove the API, or change the terms of use, and HitTail's SOL. Already they only have access to a subset of search data the API makes available, rather than all long-tail keywords, which they had a few years ago.
Will Google remain friendly to tools like this in the future? Who knows. That's a risk the new owner hopefully evaluated before taking it on.