"Security is a scaling issue" is a dangerous assumption to make. While a small site might not be targeted directly, you might still get hit by an automatic att

"Security is a scaling issue" is a dangerous assumption to make. While a small site might not be targeted directly, you might still get hit by an automatic attack if you use any off the shelf software. It's not fun when Google marks your site as harmful because your OpenX-Ad-Server suddenly serves malicious ads.