If you are using Responsive Web Design, use meta name="viewport" tag to tell the browser how to adjust the content. If you use Dynamic Serving, use the Vary HTTP header to signal your changes depending on the user-agent. If you are using separate URLs, signal the relationship between two URLs by tag with rel="canonical" and rel="alternate" elements.
An SEO technique is considered white hat if it conforms to the search engines' guidelines and involves no deception. As the search engine guidelines[18][19][52] are not written as a series of rules or commandments, this is an important distinction to note. White hat SEO is not just about following guidelines but is about ensuring that the content a search engine indexes and subsequently ranks is the same content a user will see. White hat advice is generally summed up as creating content for users, not for search engines, and then making that content easily accessible to the online "spider" algorithms, rather than attempting to trick the algorithm from its intended purpose. White hat SEO is in many ways similar to web development that promotes accessibility,[53] although the two are not identical.
Early versions of search algorithms relied on webmaster-provided information such as the keyword meta tag or index files in engines like ALIWEB. Meta tags provide a guide to each page's content. Using metadata to index pages was found to be less than reliable, however, because the webmaster's choice of keywords in the meta tag could potentially be an inaccurate representation of the site's actual content. Inaccurate, incomplete, and inconsistent data in meta tags could and did cause pages to rank for irrelevant searches.[10][dubious – discuss] Web content providers also manipulated some attributes within the HTML source of a page in an attempt to rank well in search engines.[11] By 1997, search engine designers recognized that webmasters were making efforts to rank well in their search engine, and that some webmasters were even manipulating their rankings in search results by stuffing pages with excessive or irrelevant keywords. Early search engines, such as Altavista and Infoseek, adjusted their algorithms to prevent webmasters from manipulating rankings.[12]

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;[15] 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[16] 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.

Tablet - We consider tablets as devices in their own class, so when we speak of mobile devices, we generally do not include tablets in the definition. Tablets tend to have larger screens, which means that, unless you offer tablet-optimized content, you can assume that users expect to see your site as it would look on a desktop browser rather than on a smartphone browser.
Robots.txt is not an appropriate or effective way of blocking sensitive or confidential material. It only instructs well-behaved crawlers that the pages are not for them, but it does not prevent your server from delivering those pages to a browser that requests them. One reason is that search engines could still reference the URLs you block (showing just the URL, no title or snippet) if there happen to be links to those URLs somewhere on the Internet (like referrer logs). Also, non-compliant or rogue search engines that don't acknowledge the Robots Exclusion Standard could disobey the instructions of your robots.txt. Finally, a curious user could examine the directories or subdirectories in your robots.txt file and guess the URL of the content that you don't want seen.
Mobile devices have become increasingly popular, where 5.7 billion people are using them worldwide [13]. This has played a role in the way consumers interact with media and has many further implications for TV ratings, advertising, mobile commerce, and more. Mobile media consumption such as mobile audio streaming or mobile video are on the rise – In the United States, more than 100 million users are projected to access online video content via mobile device. Mobile video revenue consists of pay-per-view downloads, advertising and subscriptions. As of 2013, worldwide mobile phone Internet user penetration was 73.4%. In 2017, figures suggest that more than 90% of Internet users will access online content through their phones.[14]
The platform of social media is another channel or site that business' and brands must seek to influence the content of. In contrast with pre-Internet marketing, such as TV ads and newspaper ads, in which the marketer controlled all aspects of the ad, with social media, users are free to post comments right below an online ad or an online post by a company about its product. Companies are increasing using their social media strategy as part of their traditional marketing effort using magazines, newspapers, radio advertisements, television advertisements. Since in the 2010s, media consumers are often using multiple platforms at the same time (e.g., surfing the Internet on a tablet while watching a streaming TV show), marketing content needs to be consistent across all platforms, whether traditional or new media. Heath (2006) wrote about the extent of attention businesses should give to their social media sites. It is about finding a balance between frequently posting but not over posting. There is a lot more attention to be paid towards social media sites because people need updates to gain brand recognition. Therefore, a lot more content is need and this can often be unplanned content.[86]

Website owners recognized the value of a high ranking and visibility in search engine results,[6] creating an opportunity for both white hat and black hat SEO practitioners. According to industry analyst Danny Sullivan, the phrase "search engine optimization" probably came into use in 1997. Sullivan credits Bruce Clay as one of the first people to popularize the term.[7] On May 2, 2007,[8] Jason Gambert attempted to trademark the term SEO by convincing the Trademark Office in Arizona[9] that SEO is a "process" involving manipulation of keywords and not a "marketing service."