I declined the spam flag, yet ended up removing the answer.
I declined the spam flag because it wasn't pure spam. While he points to his blog, he does so in an attempt to answer the question. He's not promoting a commercial product or flooding us with links to an ad-supported site. We want people to be careful with spam / offensive flags, because of the significant penalties they carry, so we tend to decline spam flags where there's no obvious product or service promotion (or other abuse, like dumping dozens of links to a site).
However, I deleted the answer because it wasn't really an answer to the question asked. We generally frown on link-only answers, and that's effectively what this one was. He didn't provide a specific solution to the question asked, he just pointed people to a generic listing of posts he's made on the topic. We want answers to be able to stand on their own, and this one didn't. Your comment to him indicated as such, and if he wants to provide a more detailed answer that doesn't require people to visit his site, but linked to his posts there as a supplement, that would be perfectly welcome.
Had you flagged this as "not an answer" or a custom flag that described what you thought the problem was, I would have gladly accepted it. As I said, we want people to be a little more cautious with the spam flags, because those shoot to the top of our queue and can carry heavy penalties.
I still appreciate you taking the time to point this out, and I wouldn't worry about a single declined flag. I have a few of them myself, and they're no real problem as long as you keep flagging like you have.