That said, I disagree with the linked article's advice on how to personalize a story for the writer you're targeting. Their example is to use a subject line like:
“Cindy – Loved your article on Buena’s robot makers + story idea”
This would be a great idea if it wasn't already abused to death. Unfortunately we constantly get pitches that begin in this format, and I now find it more annoying than anything — the compliments just seem really artificial. The worst offenders are the ones that craft subject lines to be misleading (i.e. making it sound like they have additional news to add to a story I recently wrote when their pitch is entirely unrelated).
All of that said, it's still great if you identify that a writer has expertise in a certain area and say that's why you directed your pitch to them (just hold off on complimenting them on some random article).