So I agree these are stupid, but these really are blink and you'll miss it moments. I've been watching this season and had no idea what this article was talking about.
I went back and sure enough they're there, but most are just Dexter doing Dexter things it feels more like a character recap than spoiling future events.
That being said, just because I missed both of the spoilers mentioned in the article doesn't mean they're a good idea. Once I'm watching the episode I don't need to be convinced with a sneak peek, I'm watching it.