Are we honestly that concerned with formality in this industry? I'd be more concerned with the contents and less with how formal they are. And what is wrong with using emoteicons in personal blog posts?

I don't necessarily agree with slagging off your former employer but his criticisms are still valid. The only thing that I didn't like was: "First of all I did this because this job was terrible boring for me (fixing code of other people is not especially exciting)." - That's not perhaps the best thing to write since he was a junior and this will make some people think he is lazy and does not want to take on the less fun jobs that we all have to do from time to time.

And like someone pointed out, English is not his first language. I'm sure you just didn't notice that though. :)