Another reason is that if you're using an image as a link, the alt text for that image will be treated similarly to the anchor text of a text link. However, we don't recommend using too many images for links in your site's navigation when text links could serve the same purpose. Lastly, optimizing your image filenames and alt text makes it easier for image search projects like Google Image Search to better understand your images.

In 2007, Google announced a campaign against paid links that transfer PageRank.[30] On June 15, 2009, Google disclosed that they had taken measures to mitigate the effects of PageRank sculpting by use of the nofollow attribute on links. Matt Cutts, a well-known software engineer at Google, announced that Google Bot would no longer treat any nofollow links, in the same way, to prevent SEO service providers from using nofollow for PageRank sculpting.[31] As a result of this change the usage of nofollow led to evaporation of PageRank. In order to avoid the above, SEO engineers developed alternative techniques that replace nofollowed tags with obfuscated JavaScript and thus permit PageRank sculpting. Additionally several solutions have been suggested that include the usage of iframes, Flash and JavaScript.[32]
Facebook Ads and other social media ad platforms, for example, are pay-per-click platforms that do not fall under the SEM category. Instead of showing your ads to people who are searching for similar content like search ads do, social media sites introduce your product to people who happen to be just browsing through their feeds. These are two very, very different types of online advertising.

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).[81][82][83][84][84][84] 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).[85]
There are many reasons explaining why advertisers choose the SEM strategy. First, creating a SEM account is easy and can build traffic quickly based on the degree of competition. The shopper who uses the search engine to find information tends to trust and focus on the links showed in the results pages. However, a large number of online sellers do not buy search engine optimization to obtain higher ranking lists of search results, but prefer paid links. A growing number of online publishers are allowing search engines such as Google to crawl content on their pages and place relevant ads on it.[16] From an online seller's point of view, this is an extension of the payment settlement and an additional incentive to invest in paid advertising projects. Therefore, it is virtually impossible for advertisers with limited budgets to maintain the highest rankings in the increasingly competitive search market.
LinkedIn, a professional business-related networking site, allows companies to create professional profiles for themselves as well as their business to network and meet others.[41] Through the use of widgets, members can promote their various social networking activities, such as Twitter stream or blog entries of their product pages, onto their LinkedIn profile page.[42] LinkedIn provides its members the opportunity to generate sales leads and business partners.[43] Members can use "Company Pages" similar to Facebook pages to create an area that will allow business owners to promote their products or services and be able to interact with their customers.[44] Due to spread of spam mail sent to job seeker, leading companies prefer to use LinkedIn for employee's recruitment instead using different a job portal. Additionally, companies have voiced a preference for the amount of information that can be gleaned from a LinkedIn profile, versus a limited email.[45]
Yelp consists of a comprehensive online index of business profiles. Businesses are searchable by location, similar to Yellow Pages. The website is operational in seven different countries, including the United States and Canada. Business account holders are allowed to create, share, and edit business profiles. They may post information such as the business location, contact information, pictures, and service information. The website further allows individuals to write, post reviews about businesses, and rate them on a five-point scale. Messaging and talk features are further made available for general members of the website, serving to guide thoughts and opinions.[49]

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).[79] 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:[80] 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).