Ask HN: Is Spam getting worse or is Gmail getting worse?

Over the past couple of months I've noticed that number of spam emails landing in my inbox has increased by quite a bit. I keep a very tidy inbox, so it's pretty easy for me to notice them and mark them as spam. But I'm curious: is Google just getting worse at detecting spam, or is the spam somehow evolving?

For example, I just got this email:

Sender: [email protected] Subject: the wagon is in

The body contains tons of literal HTML tags that weren't parsed into actual HTML. Not sure if it was sent as a text mime-type or what, but it takes all of 2 whole seconds for me to mentally note that this is spam.

How is this getting through more often these days?