The fact that the author wrote a sizable post about how big Python is and is growing, but then says he's more of an R type of person instead of Python. Obviously that's interesting to see when authors aren't giant fans of what they're trying to promote.

What's particularly interesting is that you can tell someone's academic pedigree from whether they use R or Python. As you mentioned, R is very popular in stats, while Python is very popular in computer science. In fact, you can tell whether other academic fields are more influenced by stats or comp. sci by this measure as well. R in econ is a great example of this, while fields that build simulations to do research tend to skew Python.