1) 40% of people will abandon a web page if it takes more than three seconds to load.

2) $1.1 trillion of all retail sales in 2011 were “web-influenced.”

3) 46% of mobile users report having difficulty interacting with a web page, and 44% complain that navigation was difficult.

4) The change in a website bounce rate spikes to 100% when a page takes 4 seconds or more to load. It jumps to 150% if a page takes 8 seconds or more to load.

5) Over 80% of marketers consider increasing overall conversion a dominant priority for their website optimization programs.

6) 78% of client-side respondents stated that their company was extremely or quite committed to delivering the best online user experience.

7) 70% of marketers resoundingly reported they are using website optimization lessons to inform offline campaigns and other marketing communications.

8) A study of Fortune 500 websites showed that 63% have content above the fold, 50% feature a scrolling content window of some kind, 63% use high quality images that connect with their users, and the average loading time is 6.5 seconds.

9) 48% of users say that if they arrive on a business site that isn’t working well on mobile, they take it as an indication of the business simply not caring.

10) 62% of companies that designed a website specifically for mobile had increased sales.

11) Only 22% of marketers say they’re ahead of the curve when it comes to responsive design. 29% say they have “average” experience level, 23% say they’re behind the times, and 4% say they’re hopeless.

12) 69% of North American marketers say dynamic, personalized content is important for their website. Only 5% say it’s of low importance.

13) Only 55% of companies are currently conducting any online user experience testing.

14) While 78% of marketers reported that their broader marketing campaigns were at least somewhat driven by website optimization results, only 47% of marketers indicated that their web design or product development actually changed as a result of optimization lessons.

15) 86.6% of U.S. SMBs cite websites as their most important digital marketing tactic.

16) 90% of people use multiple screens sequentially.

17) More than 9 out of 10 respondents (95%) agreed with the statement that “good user experience just makes sense.”

 

Source: http://blog.hubspot.com/marketing/compelling-stats-website-design-optimization-list