The importance of mobile forensics is hard to underestimate. Back in 2012, over 70% of web page requests originated from desktop and laptop computers (Windows 7 and Windows XP being the most popular systems). In May 2015, only 43% of requests come from desktop operating systems, while 54% of the traffic comes from Android, iOS, and Windows phone devices. If you look at the following graph, the trend is clear-the proportion of time the users spend with desktop computers is falling, while the use of mobile devices is rising:

Number of visitors with different OS (source: http://www.liveinternet.ru/)

At the beginning of 2015, Apple announced that it sold over one billion iOS devices. In the first quarter of 2015 alone, the company sold 74.4 million iPhone units. Android reached a billion units sold earlier in 2014.

Smartphones and tablets are successfully competing for user's attention with personal computers. They are effectively replacing digital cameras, camcorders, book readers, newspapers, communication and navigation devices, portable game consoles, and even TV. According to Flurry (http://flurrymobile.tumblr.com/post/115194107130/mobile-to-television-we-interrupt-this-broadcast#.VGukrIvF_Ex), consumers spend more time with their mobile devices than they do on TV:

Mobile to Television (Source: Flurry)

With this amount of time spent on mobile devices, and such a vast range of activities available on them, smartphones and tablets accumulate much more information about their users than we could ever imagine. Extracting this information, analyzing the data, and turning it into solid evidence is the primary goal of a digital investigator.