Social networking sites such as Facebook, Instagram, Twitter, MySpace etc. have all influenced the buzz of word of mouth marketing. In 1999, Misner said that word-of mouth marketing is, "the world's most effective, yet least understood marketing strategy" (Trusov, Bucklin, & Pauwels, 2009, p. 3). Through the influence of opinion leaders, the increased online "buzz" of "word-of-mouth" marketing that a product, service or companies are experiencing is due to the rise in use of social media and smartphones. Businesses and marketers have noticed that, "a persons behaviour is influenced by many small groups" (Kotler, Burton, Deans, Brown, & Armstrong, 2013, p. 189). These small groups rotate around social networking accounts that are run by influential people (opinion leaders or "thought leaders") who have followers of groups. The types of groups (followers) are called: reference groups (people who know each other either face-to-face or have an indirect influence on a persons attitude or behaviour); membership groups (a person has a direct influence on a person's attitude or behaviour); and aspirational groups (groups which an individual wishes to belong to).
Marketers target influential people on social media who are recognised as being opinion leaders and opinion-formers to send messages to their target audiences and amplify the impact of their message. A social media post by an opinion leader can have a much greater impact (via the forwarding of the post or "liking" of the post) than a social media post by a regular user. Marketers have come to the understanding that "consumers are more prone to believe in other individuals" who they trust (Sepp, Liljander, & Gummerus, 2011). OL's and OF's can also send their own messages about products and services they choose (Fill, Hughes, & De Francesco, 2013, p. 216). The reason the opinion leader or formers have such a strong following base is because their opinion is valued or trusted (Clement, Proppe, & Rott, 2007). They can review products and services for their followings, which can be positive or negative towards the brand. OL's and OF's are people who have a social status and because of their personality, beliefs, values etc. have the potential to influence other people (Kotler, Burton, Deans, Brown, & Armstrong, 2013, p. 189). They usually have a large number of followers otherwise known as their reference, membership or aspirational group (Kotler, Burton, Deans, Brown, & Armstrong, 2013, p. 189. By having an OL or OF support a brands product by posting a photo, video or written recommendation on a blog, the following may be influenced and because they trust the OL/OF a high chance of the brand selling more products or creating a following base. Having an OL/OF helps spread word of mouth talk amongst reference groups and/or memberships groups e.g. family, friends, work-friends etc. (Kotler, Burton, Deans, Brown, & Armstrong, 2013, p. 189). The adjusted communication model shows the use of using opinion leaders and opinion formers. The sender/source gives the message to many, many OL's/OF's who pass the message on along with their personal opinion, the receiver (followers/groups) form their own opinion and send their personal message to their group (friends, family etc.) (Dahlen, Lange, & Smith, 2010, p. 39).
Companies that employ overly aggressive techniques can get their client websites banned from the search results. In 2005, the Wall Street Journal reported on a company, Traffic Power, which allegedly used high-risk techniques and failed to disclose those risks to its clients. Wired magazine reported that the same company sued blogger and SEO Aaron Wall for writing about the ban. Google's Matt Cutts later confirmed that Google did in fact ban Traffic Power and some of its clients.
Social media can be a useful source of market information and a way to hear customer perspectives. Blogs, content communities, and forums are platforms where individuals share their reviews and recommendations of brands, products, and services. Businesses are able to tap and analyze the customer voices and feedback generated in social media for marketing purposes; in this sense the social media is a relatively inexpensive source of market intelligence which can be used by marketers and managers to track and respond to consumer-identified problems and detect market opportunities. For example, the Internet erupted with videos and pictures of iPhone 6 "bend test" which showed that the coveted phone could be bent by hand pressure. The so-called "bend gate" controversy created confusion amongst customers who had waited months for the launch of the latest rendition of the iPhone. However, Apple promptly issued a statement saying that the problem was extremely rare and that the company had taken several steps to make the mobile device's case stronger and robust. Unlike traditional market research methods such as surveys, focus groups, and data mining which are time-consuming and costly, and which take weeks or even months to analyze, marketers can use social media to obtain 'live' or "real time" information about consumer behavior and viewpoints on a company's brand or products. This can be useful in the highly dynamic, competitive, fast-paced and global marketplace of the 2010s.
The criteria and metrics can be classified according to its type and time span. Regarding the type, we can either evaluate these campaigns "Quantitatively" or "Qualitatively". Quantitative metrics may include "Sales Volume" and "Revenue Increase/Decrease". While qualitative metrics may include the enhanced "Brand awareness, image and health" as well as the "relationship with the customers".
These posts can be one or more of the following: images, photo sets, animated GIFs, video, audio, and text posts. For the users to differentiate the promoted posts to the regular users' posts, the promoted posts have a dollar symbol on the corner. On May 6, 2014, Tumblr announced customization and theming on mobile apps for brands to advertise.
By 2004, search engines had incorporated a wide range of undisclosed factors in their ranking algorithms to reduce the impact of link manipulation. In June 2007, The New York Times' Saul Hansell stated Google ranks sites using more than 200 different signals. The leading search engines, Google, Bing, and Yahoo, do not disclose the algorithms they use to rank pages. Some SEO practitioners have studied different approaches to search engine optimization, and have shared their personal opinions. Patents related to search engines can provide information to better understand search engines. In 2005, Google began personalizing search results for each user. Depending on their history of previous searches, Google crafted results for logged in users.
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. 
Inbound marketing refers to a marketing methodology wherein you attract, engage, and delight customers at every stage of the buyer's journey. You can use every digital marketing tactic listed above, throughout an inbound marketing strategy, to create a customer experience that works with the customer, not against them. Here are some classic examples of inbound marketing versus traditional marketing: