Email remains the most effective digital marketing tool for both B2B and B2C marketers. But the majority of email activity now takes place on mobile devices, and not all marketers have effectively adapted to this rapid shift.

Those are just a couple of the findings in the nearly four dozen email and mobile marketing facts and statistics from 15 different sources compiled below. Five more key takeaways from this research:

Most popular activities on smartphones

Image credit: emailmonday

Email marketing works—for both sellers and buyers. Digital marketers rank email as their most effective marketing tactic, and say it has the highest ROI of any digital channel. It’s also the most effective digital tactic in B2B marketing, with nearly a third of B2B marketers saying it has the biggest impact on revenue. And 72% of U.S. adults prefer communication with companies to happen through email.

Personalized email subject lines: effective, but underused. For B2C emails, personalized subject lines increase the open rate by 41%, and lead to higher transaction rates and revenue per email. Yet only 35% of brands personalize their subject lines.

Mobile email marketing lags consumer adoption. Email is increasingly mobile. The number of mobile email users rose 22% last year and is projected to grow another 23% in 2016. In the second quarter of 2015, roughly two-thirds of emails were opened on mobile devices, with more than half opened on smartphones. Yet 51% have either no strategy for mobile email or only the basics for mobile email optimization in place.

Mobile advertising spending up through results are uncertain. U.S. marketers increased their spending on mobile advertising by 50% in 2015 over the previous year, and the share of budget dollars allocated to mobile marketing is projected to triple in the next three years. Yet most senior marketers say today’s mobile marketing effort perform poorly; 8 in 10 have difficulty tracking mobile ROI; and half of all clicks on mobile ads are accidental.

B2B mobile marketing growing but still small. The percentage of B2B marketing dollars devoted to mobile is expected to nearly triple by 2018but still account for only 14% of total spending. And while mobile use for B2B purchase research has jumped 91% in the past two years, more than three-quarters of global business executives still prefer to browse content on their laptops or desktops.

And now on to the 45 phenomenal email and mobile marketing stats and facts. Enjoy!

14 Email Marketing Stats and Facts

1. The number of email users worldwide is currently 2.6 billion and is expected to grow to over 2.9 billion by 2019. (MediaPost)

2. A large majority of U.S. adults — 72% — prefer communication with companies to happen through email. (MarketingSherpa)

3. Email is the only digital channel that outperforms old media standbys in terms of how consumers prefer communcations with companies — postal mail (preferred by 48%), television ads (preferred by 34%) and print media, such as magazines and newspapers, (preferred by 31%). Only 11% of people prefer mobile apps and just 7% prefer online video ads. (MarketingSherpa)

4. Email is the most effective digital marketing tactic for B2B marketers, with 31% saying it has the biggest impact on revenue. (MarketingProfs)

5. Across all age groups, email is the preferred method of commuicating with companies (with about three-quarters of consumers/buyers choosing this). However, while more than 60% of those aged 55 and older like to communicate with companies by postal mail, just 29% of millennials say the same. (MarketingSherpa)

6. Personalized email subject lines increase open rates–but the effect varies considerably across industries. Personalizing the subject line increases open rates for consumer products and services by 41%, versus 13% for B2B emails. (MarketingSherpa)

7. For consumer products and services, personalizing email subject lines also increases transaction rates by 49%, and revenue per email by 73%. (MarketingSherpa)

8. And yet–only 35% of brands personalize their email subect lines. (MarketingSherpa)

9. 46% of startups use email marketing. (TNW News)

10. Digital marketers rank email as their top marketing tactic, with 54% saying it’s their most effective channel and just 11% calling it the most difficult. Mobile marketing and SMS, however, ranked near the bottom in the same survey, with just 9% citing it as their most effective tactic while 34% viewed it as the most difficult. (TNW News)

11. Email is viewed as the most effective digital marketing tactic for customer retention purposes. But while 56% of marketers viewed email as an effective retention tactic, just 8% said the same for mobile advertising. (TNW News)

12. Direct marketers say email has the highest ROI of any marketing tactics. Mobile falls near the bottom of the list, however, below direct mail and just ahead of paid search advertising. (TNW News)

13. Asked about all the different devices they use to open and read emails, 93% of consumers use a laptop or desktop computer; 67% use a smartphone; and 42% use tablets. (Email Monday)

14. Asked why they unsubscribe from brand emails, 33% of consumers said they do so because mailings are too frequent. 24% unsubscribe because the content is repetitive and boring. (SocialTimes)

5 Mobile Marketing Stats and Facts

15. 57% of consumers will not recommend a business with a poorly designed mobile site. (Payfirma)

16. 61% of people have a better opinion of brands when they offer a good mobile experience. (Payfirma)

17. 73% of all the people on earth (5.2 billion) are mobile phone users. 40% of those (just over two billion) own smartphones. (Mary Meeker’s Internet Trends)

18. 44% of millennials use their smartphones’ camera or video functions at least daily; an astounding 87% use those features at least once per week. 76% share photos and video on social media. (Mary Meeker’s Internet Trends)

19. Mobile accounted 45% share of US organic search traffic in the first part of 2015 (based primarily on retail / B2C client data). The iPhone (18%) and iPad (12%) alone contributed a combined 30% of organic search traffic. (e-Strategy Trends)

7 Mobile Email Stats and Facts

20. Two-thirds of all U.S. emails were opened via mobile in the first quarter of last year. Half were accessed on smartphones, and 17% occurred on a tablet, with the remaining 33% being opened on your traditional desktop. (V3 Broadsuite Blog)

21. The number of mobile e-mail users is predicted to grow 22% in 2015 and 23% in 2016. (Email Monday)

22. 17% of marketers admit they have no strategy for mobile email, while 34% have the basics for mobile email optimization in place. Just 21% say they have an advanced mobile email strategy. (Email Monday)

23. A study of B2C (primarily retail) email campaigns found that in the first quarter of 2015, mobile opens (50.12%) have surpassed desktop opens (32.97%). What’s more, 36.6% of people make purchases on a desktop, while 49.3% of people make purchases on smartphones. (MarketingSherpa)

24. In the second quarter of 2015, nearly 68% of emails were opened on a mobile device, with 52% of those being opened on smartphones. The desktop saw just over 32 percent of email opens. (MarketingLand)

25. However–almost 53% of all conversions in 2Q15 were on the PC. Smartphones drove 29% of conversions and tablets 18%. (MarketingLand)

26. The iPhone is the single dominant mobile email reading device, but its users spend the least amount of time looking at individual emails. Mobile devices drive more opens but far fewer conversions (example: iPhone: 42% of opens, 18% of conversions). (MarketingLand)

8 Mobile Advertising Stats and Facts

27. The share of budget dollars spent on mobile marketing by B2B marketers is expected to nearly triple in the next three years, from 5% today to about 14%. B2C marketers plan to increase the portion of budgets spent on mobile from 8% today to about 20%–even though most senior marketers say today’s mobile marketing efforts perform poorly. (The CMO Survey)

28. Total online ad spending in the U.S. is $50 billion, of which $13 billion is spent on mobile ads. (Mary Meeker’s Internet Trends)

29. 8% of total U.S. ad spending is on mobile, though it accounts for 24% of all media consumption. Meanwhile, 18% of all ad spending is on print–which accounts for just 4% of media use. (Mary Meeker’s Internet Trends)

30. The media and entertainment industries have been aggressive with mobile marketing. Advertising on mobile devices accounted for nearly 54% percent of digital ad spending in the entertainment industry in 2015. Media brands devoted 51% of their digital advertising spending to mobile, with 51 percent. (V3 Broadsuite Blog)

31. And yet–when conducting research to help make significant business decisions, 78% of global business executives prefer to browse content on their laptop or desktop computers (vs. 7% for smartphones). (MarketingSherpa)

32. U.S. marketers increased their spending on mobile advertising by 50% over 2014 to $28.72 billion in 2015. (MediaPost)

33. Despite its projected growth, however, much of the impact of mobile marketing is still difficult to measure. Nearly eight in 10 U.S. marketers said they would increase spending on mobile if they could track return on investment (ROI) better. (MediaPost)

34. About 50% of clicks on mobile ads are accidental. (GoldSpot Media)

4 Mobile Shopping Stats and Facts

35. One in four mobile online shoppers in the US is over the age of 55. (Payfirma)

36. Mobile is projects to account for 25% of all U.S. online sales by 2017, and mobile devices will account for 30% of global retail e-commerce spending by 2018. (Payfirma)

37. 90% of those aged 18-35 have used their mobile device in store. (Payfirma)

38. Email marketing typically represents about 20% of retail traffic, and often a higher share of orders (25-30% for some retailers). While phones represent about 18% of orders, over 50% of emails are opened on phones. (MarketingSherpa)

4 Mobile Social Media Stats and Facts

39. Facebook and Twitter reported that mobile revenue in 2Q15 made up 76% and 88% of their total revenue, respectively. (MediaPost)

40. Marketers who use email in combination with social sharing can drive six times more revenue. Social sharing buttons have been shown to push click-through rates 158% higher. (MediaPost)

41. 189 million Facebook users are “mobile only.” (Cloudswave)

42. 27% of brand mentions on Twitter come from an iPhone and 18% come from an Android device. 21% come from a web browser. (Infini Datum)

3 B2B Mobile Marketing Statistics

43. 42% of B2B buying researchers use a mobile device during the B2B purchasing process. Mobile use for B2B purchase research has grown 91% in the past two years. (MediaPost)

44. 49% of B2B researchers who use their mobile devices for product research do so while at work. They’re comparing prices, reading about products, comparing feature sets and contacting retailers. They’re purchasing, too; purchase rates on mobile are up 22% in the past two years. (MediaPost)

45. 89% of B2B technology marketers say they use email to market their products. However, just 15% run mobile campaigns. (MarketingProfs)