Following up on our last class, I found this article and the case it discusses interesting for various reasons. It indicates to me that even the largest companies might still have difficulties to declare questionable (e.g. because rather obvious) patents invalid. Furthermore, it did not surprise me that this case again was against a patent troll.
I found the court’s reasoning regarding the differing relevance of “common sense” in respect of combining prior inventions and adding a new element to a prior invention interesting. Nevertheless, I was not fully convinced by this argument and the court’s distinction.
At the same time, even more interesting to me was the fact that DDS, while having started and grown as a patent troll (as described in the article from 2007 linked in your post), seemingly had been able to grow a “real” core business during the last years, as described in the following article:
https://seekingalpha.com/article/1631742-document-security-systems-all-aboard-before-its-too-late