Analyzing the Top 10,000 Websites' HTTP Headers
shodanhq.com
shodanhq.com
I'm worried to think how site operators will adopt CSP (Content Security Policy) once it starts to gain traction.
What would I type into wget or curl to download the "banner" of a site?
By default the browser will be in it's more secure state and those headers actually drop the security to allow cross communication with (specific) other websites.