Whether Google is considered a semantic search engine really depends on your definition of “semantic” in the context of the Web and a search engine specifically. It is clear from the post that there are differing interpretations of the semantic web and what constitutes the semantic web and this would play into your thinking about this.
The conclusion of the post is a mixed one. On one hand Google demonstrates elements of what could be expected from a semantic search engine and on the other hand it isn’t quite there yet. I wonder if becoming a semantic search engine isn’t perhaps as a result of more evolved search algorithms – as the algorithms become more advanced, meaning begins to seep into the search results and the whole system begins to learn what we find meaningful in particular contexts.