Update: Google’s official announcement is now live.

Much of Google’s work in search this year, as well as its guidance for webmasters, has been related to mobile search. Google has really ramped up its efforts of late to improve the mobile search experience, as more and more people perform more and more searches from their smartphones.

Now, the company is putting a special emphasis on sites that are “mobile-friendly,” while giving them possible ranking boosts.

Barry Schwartz at Search Engine Land reports (we’re not seeing the official announcement on the web just yet) that Google has officially launched the mobile-friendly label in mobile search results, while Danny Sullivan says Google is “experimenting” with giving sites that have earned the label “some type of special treatment within its ranking algorithm”.

Sullivan shares this quote from a Google post, which doesn’t appear to be live yet: “We see these labels as a first step in helping mobile users to have a better mobile web experience. We are also experimenting with using the mobile-friendly criteria as a ranking signal.”

According to Schwartz’s report, sites can earn the label by avoiding software that’s not common on mobile devices (such as Flash), using readable (without zooming) text, sizing content to the screen so users don’t have to scroll horizontally or zoom, and placing links far enough apart so the right one can easily be tapped.

Menawhile, Google is asking mobile users to rate search results.

A couple weeks ago, Google announced a new feature in Webmaster Tools to help webmasters track mobile usability.

Prior to that, it had been notifying webmasters about sites with faulty redirects in mobile results to save users the “common annoyance” of tapping a search result only to be redirected to a site’s mobile homepage. Google has also been noting when pages “may not work on your device” because of things like Flash.

Images via Google