Wow. What a wonderful communication and acknowledgment! I'm pretty sure I can speak for Matt and all the other developers who have dedicated their personal time and effort to contributing to HTM.java - also when I say, "Thank you, so much!" Matt has done a wonderful job nurturing and building the HTM community and it has not only been a privilege to be a part of that, but also very life-changing as well. So again, thank you Joe.
To answer your question, I actually have worked quite extensively in KNIME (through my job with Cortical.io). I'm not exactly free to say what Cortical.io's involvement is with it since it is an internal project, but there has been a lot of attention focused on that technology. I agree that it is a wonderful technology with a lot of utility for machine intelligence/learning and streaming-data driven applications.
Unfortunately, the work was at least put on hold because they have a heavy investment in the older "Swing" technology (JavaFX is the current UI Toolkit moving forward), and it kind of "shackled" KNIME development to Java 7 and below... I can't really speak of the current status of it though because their slow or stunted adoption of Java 8 caused us to put it on the back burner so to speak. To be fair, migrating to Java 8 is a particular challenge for KNIME because of the extent of Eclipse integration within that platform. This means the necessity for bridging technology between SWT (their native UI Toolkit) to the newer JavaFX - which Eclipse isn't natively poised for doing makes it a bit difficult to extend (at least that's my take on why it has been slow to arrive). I think it has been several months since I "dropped in" to see what the current status is with Java 8 adoption, but as you may or may not know, Java 8 is the minimum Java version for HTM.java.
Java 8 brought with it such radical and beneficial enhancements to the Java language that I decided not to maintain two different versions of HTM.java and make full use of the newest API (i.e. Streams within the Network API). As such, there are many places where the use of lambdas and other Java 8 specific constructs are used, and to use it with KNIME would mean to basically maintain two versions of the same codebase - something I just don't have enough time (nor any interest at all) in doing.
That being said, I believe it would be technically possible to "downgrade" the individual algorithms to Java 7 - mostly because this is something I did for Cortical.io, but the Network API is a total non-starter for Java 7. I believe it would be possible for an extraordinarily committed individual with lots of free time to do - but I really wouldn't recommend it. This I say mainly because HTM.java is likely to change very much in the upcoming weeks and months (to keep pace with algorithm improvements etc.); making maintenance of a Java 7 version a total nightmare going forward.
Are you aware of any change in the status of their Java 8 support? It would definitely be worth while to keep an eye on the possibility of Java 8 adoption - and if and when it becomes available, this would become a much encouraged avenue for HTM.java expansion!
Anyway thanks again for your kind words and for your interest in HTM.java.