Strict Transport Security (STS) has gone live on PayPal yesterday.
STS is a simple yet effective system for web sites requiring high safety levels, e.g. payment gateways or financial institutions, to force HTTPS connections on every request originated by supporting browsers.
It is currently supported by NoScript, Chrome 4 beta and Sid Stamm's Force TLS.
Together with NoScript's anti-XSS protection, this feature makes PayPal a much safer service for NoScript users.