It's what your data "show." Not what your data "shows." I am always skeptical of the analytical competence of someone who uses incorrect language to describe their own work.
In this case their data is a collection or mass of data - and is singular. In the blog, using "the data shows that" is the proper way to write the statement.
If the majority of people refer to collective nouns as singular than that is the correct way to use them because the "correct way" is only ever defined by the majority.
How is the pronunciation of a word decided? Majority of people saying it one way. How do people agree upon the meaning of a word? Majority of people using it to mean something. How does grammar become more lax? Majority of people speak with fewer restrictions.
i contest the moderne way of speech is to be thovght proper as he has argvede, bvt the olde way of speeking is the trve way!