A few days ago, Google announced on their webmaster central blog that HTTPS is now one of the various ranking signals that Google uses to determine website rank. They are careful to state that it is [currently] only a very minor ranking factor, but it may become more important in the future. The original article can be found at http://googlewebmastercentral.blogspot.com/2014/08/https-as-ranking-signal.html.
HTTPS is the secure, encrypted protocol used to transfer web content to browsers. Enabling HTTPS requires the website owner to purchase or acquire a "certificate" that is trusted by browsers. These can vary from free to thousands of dollars per year, depending on the level of verification that certificate providers perform to validate that you are who you say you are. Banks and other financial institutions, for example, frequently use the EV or "Extended Validation" certificates to reassure visitors that they are actually on the bank's website and not a phishing site.
The internet community is mostly united, saying that this move by Google is a good thing. In general, HTTPS internet traffic cannot be snooped on by anyone in the middle who has access to your web traffic. This ranges from people at coffee shops to your employer, and even the network provider themselves. A more secure internet is a better internet.
The downside is, of course, the extra cost. While Google has not indicated if any less weight will be assigned to sites using the "free" certificates, most companies will choose to purchase one from one of the reputable certificate authorities. Additionally, any site using HTTPS is required to have it's own dedicated IP address—something that is in dangerously short supply. Most hosting providers charge extra for additional IP addresses. On the other hand, this monetary burden only helps to establish the authority of sites that properly implement HTTPS.