Facebook pages are far more detailed than Twitter accounts. They allow a product to provide videos, photos, longer descriptions, and testimonials where followers can comment on the product pages for others to see. Facebook can link back to the product's Twitter page, as well as send out event reminders. As of May 2015, 93% of businesses marketers use Facebook to promote their brand. A study from 2011 attributed 84% of "engagement" or clicks and likes that link back to Facebook advertising. By 2014, Facebook had restricted the content published from business and brand pages. Adjustments in Facebook algorithms have reduced the audience for non-paying business pages (that have at least 500,000 "Likes") from 16% in 2012 down to 2% in February 2014. 
On April 24, 2012 many started to see that Google has started to penalize companies that are buying links for the purpose of passing off the rank. The Google Update was called Penguin. Since then, there have been several different Penguin/Panda updates rolled out by Google. SEM has, however, nothing to do with link buying and focuses on organic SEO and PPC management. As of October 20, 2014 Google has released three official revisions of their Penguin Update.
Social networks are, in many cases, viewed as a great tool for avoiding costly market research. They are known for providing a short, fast, and direct way to reach an audience through a person who is widely known. For example, an athlete who gets endorsed by a sporting goods company also brings their support base of millions of people who are interested in what they do or how they play and now they want to be a part of this athlete through their endorsements with that particular company. At one point consumers would visit stores to view their products with famous athletes, but now you can view a famous athlete's, such as Cristiano Ronaldo, latest apparel online with the click of a button. He advertises them to you directly through his Twitter, Instagram, and FaceBook accounts.
Another example when the “nofollow" attribute can come handy are widget links. If you are using a third party's widget to enrich the experience of your site and engage users, check if it contains any links that you did not intend to place on your site along with the widget. Some widgets may add links to your site which are not your editorial choice and contain anchor text that you as a webmaster may not control. If removing such unwanted links from the widget is not possible, you can always disable them with “nofollow" attribute. If you create a widget for functionality or content that you provide, make sure to include the nofollow on links in the default code snippet.
On Google+ you can upload and share photos, videos, links, and view all your +1s. Also take advantage of Google+ circles, which allow you to segment your followers into smaller groups, enabling you to share information with some followers while barring others. For example, you might try creating a “super-fan” circle, and share special discounts and exclusive offers only with that group.
In early 2012, Nike introduced its Make It Count social media campaign. The campaign kickoff began YouTubers Casey Neistat and Max Joseph launching a YouTube video, where they traveled 34,000 miles to visit 16 cities in 13 countries. They promoted the #makeitcount hashtag, which millions of consumers shared via Twitter and Instagram by uploading photos and sending tweets. The #MakeItCount YouTube video went viral and Nike saw an 18% increase in profit in 2012, the year this product was released.
In some contexts, the term SEM is used exclusively to mean pay per click advertising, particularly in the commercial advertising and marketing communities which have a vested interest in this narrow definition. Such usage excludes the wider search marketing community that is engaged in other forms of SEM such as search engine optimization and search retargeting.
On the other hand, marketers who employ digital inbound tactics use online content to attract their target customers onto their websites by providing assets that are helpful to them. One of the simplest yet most powerful inbound digital marketing assets is a blog, which allows your website to capitalize on the terms which your ideal customers are searching for.