In response to recent leaks of harvested data being sent to the NSA from big providers, Google is now always using an encrypted HTTPS connection when users check or send mail. Additionally, Google claims that 100% of users' emails are encrypted when moving between Google's data centers, something the company calls "a top priority after last summer's revelations."
The official blog post noting the change claims that "today's change means that no one can listen in on your messages as they go back and forth between you and Gmail's servers -- no matter if you're using public Wi-Fi or logging in from your computer, phone or tablet."
Also discussed was Google's reliability record. The company claims that in 2013, Gmail was available 99.978% of the time. The high percentage equates to an average of two hours of disruption for any given user over the entire year.