CTR matters because it is a metric that can be controlled by marketers. However, while Google’s emphasis on CTR should be noted, it is also important that marketers don’t get tunnel vision with improving CTR. It is not an uncommon mistake for marketers to focus primarily on improving CTR… to their detriment. Creating highly attractive ads for the sole purpose of increasing CTR could be a costly error that ultimately impact your account history, especially if the ads are misleading and result in high bounce rates.
Links - Links from other websites play a key role in determining the ranking of a site in Google and other search engines. The reason being, a link can be seen as a vote of quality from other websites, since website owners are unlikely to link to other sites which are of poor quality. Sites that acquire links from many other sites gain authority in the eyes of search engines, especially if the sites that are linking to them are themselves authoritative.
From an SEO perspective, there is no difference between the best and worst content on the Internet if it is not linkable. If people can’t link to it, search engines will be very unlikely to rank it, and as a result the content won’t drive traffic to the given website. Unfortunately, this happens a lot more often than one might think. A few examples of this include: AJAX-powered image slide shows, content only accessible after logging in, and content that can't be reproduced or shared. Content that doesn't supply a demand or is not linkable is bad in the eyes of the search engines—and most likely some people, too.
PageRank was once available for the verified site maintainers through the Google Webmaster Tools interface. However, on October 15, 2009, a Google employee confirmed that the company had removed PageRank from its Webmaster Tools section, saying that "We've been telling people for a long time that they shouldn't focus on PageRank so much. Many site owners seem to think it's the most important metric for them to track, which is simply not true."[65] In addition, The PageRank indicator is not available in Google's own Chrome browser.
PageRank is a link analysis algorithm and it assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of "measuring" its relative importance within the set. The algorithm may be applied to any collection of entities with reciprocal quotations and references. The numerical weight that it assigns to any given element E is referred to as the PageRank of E and denoted by {\displaystyle PR(E).} Other factors like Author Rank can contribute to the importance of an entity.

Another excellent guide is Google’s “Search Engine Optimization Starter Guide.” This is a free PDF download that covers basic tips that Google provides to its own employees on how to get listed. You’ll find it here. Also well worth checking out is Moz’s “Beginner’s Guide To SEO,” which you’ll find here, and the SEO Success Pyramid from Small Business Search Marketing.

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