Though social media marketing has become ubiquitous, most companies and brands still struggle to achieve their desired results. Or to accurately measure their results. Or to set the right goals to begin with.

Those are among the conclusions it’s fair to draw from the collection of social media marketing facts and statistics below. Eights years after social media marketing became a trending topic, marketers still struggle with tactics and metrics.

In fairness, part of this is due to the difficulty of hitting a moving target. As consumer and business buyer use of social media has matured and become more sophisticated, their expectations of brands in social media have evolved as well.

And ongoing changes by Facebook and other social networks that result in lower organic reach render many of yesterday’s effective marketing tactics far less useful today.

Here are five key takeaways from the research below.

Social media needs to be part of an integrated strategy. 90% of companies now use social media for business—yet most aren’t certain it adds value to the bottom line, and more than 60% have trouble assessing its impact or turning metrics in actionable ideas. Those who can measure results directly have discovered social media is far less effective at driving direct purchases than email or search advertising.

The answer isn’t to give up on social media, but to recognize it’s not great for direct response. Social media marketing is valuable, however, for enhancing brand presence and image online, and plays a key role in an overall web presence optimization strategy.

Advertising needs to be part of social media strategy. As noted below, organic reach is now less than 2%. It’s never been great on Twitter, and recent changes LinkedIn made to Groups functionality reduces their value.

Many marketers get this: spending on social network advertising is expected to double in the next five years. The good news: social ads are highly targetable and (at least for now) relatively affordable.

Social is for customer service. Engaging current customers on social media is much more common that engaging prospects. 84% of marketers believe social media can enhance existing customer relationships. Nearly two-thirds of social media users expect brands to offer customer service via social networks. And your prospective buyers—they are watching.

Influencer marketing? Think small. Pursuing the industry influencers with the largest follower counts may not be the best strategy. They are overwhelmed with brand pitches. Meanwhile, 91% of brand/company mentions on social networks come from people with fewer than 500 followers—and 94% of those mentions are positive.

Your best influencers are often your own employees (but train them). Your customers will share your content too—but only if it’s the kind of content that meets their idea research needs, not just marketing fluff.

Say it with images. It’s been said “a picture is worth a thousand words,” and nowhere is that more true, apparently, than in social media. Followers value images, videos, and case studies as the most valued content from brands on social media. Yet 58% of marketers say written content is their most important form of social content; just 19% say that of original visual content. Clearly a disconnect (and therefore an opportunity).

Find these and more actionable takeaways in this collection of three dozen social media marketing stats and facts.

Stats and Facts About Social Media Strategy and Tactics

1. 90% of companies now use social media for business purposes – up from 60% in 2013. (iMedia Connection)

2. But social media is not effective at directly driving purchases — it accounts for just 1% of e-commerce sales, compared to 16% for email and 17% for CPC. (Experience: The Blog)

3. The top eight social networks collectively now drive more than 30% of overall traffic to websites. (iMedia Connection)

4. Facebook, Twitter and Pinterest drive the most social media referral traffic back to websites. But YouTube, Google+ and LinkedIn drive the most engaged traffic. (Buffer)

5. Other than the nonprofit/education sector, retail & ecommerce have the highest level of social media engagement (people love their fashion and food brands), followed by manufacturing. (MarketingSherpa)

6. The real estate industry has (by far) the lowest level of engagement (one “share” for every 19 social posts), followed by marketing services and software/tech. (MarketingSherpa)

7. Advertisers are expected to spend $12.3 billion on social marketing in 2015. By 2020, it’s projected brands will spend a whopping $27 billion on social media. (iMedia Connection)

8. Advertising now needs to be part of social media strategy. Organic reach for top brands is less than 2% on Facebook. (Experience: The Blog)

9. 62% of marketers say designing an overall social media strategy is the biggest challenge their companies face with social media. (eMarketer)

10. Rethink “influencer” marketing? 91% of brand/company mentions on social networks come from people with fewer than 500 followers. And 94% of those mentions are positive. (Buffer)

11. Then again, your best “influencers” may be your own employees. 50% of employees share about their company on social media (without any prompting). (iMedia Connection)

12. But – some training and guidance are needed. Just 41% of U.S. employees say they know what their company stands for and what makes its brand different from competitors’ brands. (iMedia Connection)

13. Want to hold on to your company’s hard-earned social media following? Put your customers’ needs an interest first. 21% of consumers say they unfollow brands that post repetitive or boring content. 19% say they would unfollow a brand on Facebook if the brand posted too often – more than six times a day. (SocialTimes)

14. 75% of B2B buyers want brands to furnish substantive content that helps them to research business ideas, but 93% of brands focus their content on “marketing” their own products and services. (MarketingCharts)

15. Finally, remember that not everyone is on social media; more than 50% of internet users either don’t use any social networks or use only one. (iMediaConnection)

Stats and Facts About Social Metrics and Measurement

16. Just 38% of marketers strongly agree that analyzing social media engagement data can help improve their bottom line. About half “somewhat agree,” and 15% don’t think analyzing social media matters at all to the bottom line. (eMarketer)

17. Two-thirds of marketers say “assessing the effectiveness of social media activities” is the biggest challenge with social media their companies face. 61% say turning social media data into actionable plans is a top challenge. (eMarketer)

18. 44% of companies still don’t measuring social’s value in their organizations. (iMediaConnection)

Social Content Stats and Facts

19. 58% of marketers say original written content is their most important form of social content. 19% say the same about original visual content (e.g., infographics). 10% say curation of others’ content (like this post) is most important. (Buffer)

20. From the customer side, the three brand social media activities that matter most to followers are new content in posts, content that is relevant to the brand, and engagement with followers. (SocialTimes)

21. Followers value images, videos, and customer reviews from brands most highly on social media. They place the least value on white papers and ebooks. (SocialTimes)

22. Posts with videos attract three times as many inbound links as plain text. (iMedia Connection)

Stats About Social Media Post Timing

23. The best time of the day for generating retweets is between 9:00 p.m. and midnight eastern time in the U.S. Late afternoon (between 4:00 and 5:00 p.m. ET) is also good. (Buffer)

24. Friday is the best day of the week for generating engagement on Facebook. And use photos: 87% of all Facebook page interactions happen on photo posts. (Buffer)

25. Thursday is the best day of the week for engagement with fashion image on Pinterest. Tuesday is the best day for technology pins. (Buffer)

Social Customer Service Stats and Facts

26. 84% of marketing professionals think social media can enhance relationships with existing customers. (eMarketer)

27. One in three social media users prefer to reach out to a brand on social media for customer service, and 63% expect companies to offer customer service on social media. 75% of consumers using social media expect to hear from customer service in an hour or less. (Cognizant)

28. 25% of consumers who complain about products on Facebook and Twitter expect a response to their gripes within one hour. (iMediaConnection)

29. 53% of people who tweet at a brand expect a response within one hour. That figure rises to 72% for those with a complaint. Just 14% anticipate a response will take a full day or longer. (Buffer)

30. However–just 8% of people say they will unfollow a brand on Twitter due to lack of engagement (slow or no response to comments). (SocialTimes)

Facebook Facts and Stats

31. Is Facebook losing its cool? More than 11 million young people have abandoned Facebook since 2011. (iMediaConnection)

32. But Facebook remains the dominant social network. 59% of users access Facebook two or more times a day — which is two-thirds more than Snapchat or Twitter and 1000% more than Pinterest. (Experience: The Blog)

33. Consumers expect brands to be present on at least three different social networks, and 80% expect brands to be present on Facebook. (Experience: The Blog)

Other Social Networking Facts and Stats

34. The nonprofit/education industry averages (by far) the most social interactions per post on Facebook, Twitter, Google Plus and LinkedIn — even though they likely have the smallest budgets and the least resources to dedicate to social media marketing. (MarketingSherpa)

35. At least 10% of Twitter accounts are fake. (NBC News)

36. While “unfollowing” companies is common on Facebook and Twitter, 49% of people say they never unfollow brands on LinkedIn. (SocialTimes)