Hi. Increasingly we're seeing a lot of traffic from mobile browsers that are part of a content sharing app. This can be the Facebook, Twitter, Google Search app, Instapaper, etc.
Here's some examples:
This is the user-agent data for the Facebook app browser for iPhone:
Mozilla/5.0 (iPad; CPU OS 6_1_3 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Mobile/10B329 [FBAN/FBIOS;FBAV/5.6;FBBV/144493;FBDV/iPad3,1;FBMD/iPad;FBSN/iPhone OS;FBSV/6.1.3;FBSS/2; FBCR/;FBID/tablet;FBLC/en_US;FBOP/0]
This is one for the Twitter app browser for iPhone:
Mozilla/5.0 (iPad; CPU OS 6_1_3 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Mobile/10B329 Twitter for iPhone