Page title – The page title is one of the most important (if not even the most important) in-page SEO factor; it not only tells search engine what a page is about, but it is also displayed in SERPS and on visitors browsers. So a page title may be at the same time user friendly (make the people click on it on SERPS) and search engine friendly (include the keywords and as less other words as possible). It is also called title tag.

PageRank (PR) ­– The PageRank (PR) is Google’s official measurement unit for link popularity, varying from 0 (which any brand new site starts with) to 10 (which is the very best a site can achieve); the growth however is not linear, but exponential (having two times more links than a PR 5 site won’t grant a PR 10, but more likely only a PR 6). Mainly every back link carry a certain amount of link popularity; the higher the PR of the site where the link is placed and the lower the number of outgoing link on that page – the higher the link popularity or PR that is passed to the target site.

Paid placement – A paid placement in a search engine or directory signifies the fact that the site paid for the listing; most of the times the paid listings are less relevant than the organic results. It is also called sponsored placement.

Pay-per-click (PPC) – The pay-per-click (PPC) model is the most used advertising model nowadays; in this model the advertiser pays a publisher for each and every click made on the advertising. Google AdWords is the most popular pay-per-click (PPC) advertising program.