Online visibility

Search engine optimization (SEO) is the process of affecting the visibility of a website or a web page in a search engine's "natural" or un-paid ("organic") search results.[jargon] In general, the earlier (or higher ranked on the search results page), and more frequently a site appears in the search results list, the more visitors it will receive from the search engine's users. SEO may target different kinds of search, including image search, local search, video search, academic search,[1] news search and industry-specific vertical search engines.

Sources: SEO Wikipedia

Search engine marketing (SEM) is a form of internet marketing that involves the promotion of websites by increasing their visibility in search engine results pages (SERPs) through optimization (both on-page and off-page) as well as through advertising (paid placements, contextual advertising, and paid inclusions).^[1] Depending on the context, SEM can be an umbrella term for various means of marketing a website including search engine optimization (SEO), which adjusts or rewrites website content to achieve a higher ranking in search engine results pages, or it may contrast with pay per click (PPC), focusing on only paid components.^[2]

Source: http://en.wikipedia.org/wiki/Search_engine_marketing

Pay per click (PPC) (also called cost per click) is an Internet advertising model used to direct traffic to websites, where advertisers pay the publisher (typically a website owner) when the ad is clicked. With search engines, advertisers typically bid on keywordphrases relevant to their target market. Content sites commonly charge a fixed price per click rather than use a bidding system. PPC "display" advertisements, also known as "banner" ads, are shown on web sites or search engine results with related content that have agreed to show ads. This approach differs from the "pay per impression" methods used in Facebook, television and newspaperadvertising. Similar to the pay per click model which often uses a bidding system, with the online pay per impression method, advertisers bid how much they are willing to spend for their ad to show up 1000 times.

 Source: http://en.wikipedia.org/wiki/PPC

Social search or a social search engine is a type of web search that takes into account the Social Graph of the person initiating the search query. When applied to web search this Social-Graph approach to relevance is in contrast to established algorithmic or machine-based approaches where relevance is determined by analyzing the text of each document or the link structure of the documents.^[1] Search results produced by social search engine give more visibility to content created or touched by users in the Social Graph.

Social search takes many forms, ranging from simple shared bookmarks or tagging of content with descriptive labels to more sophisticated approaches that combine human intelligence with computer algorithms.^{[2][3] [4][5]}

The search experience takes into account varying sources of metadata, such as collaborative discovery of web pages, tags, social ranking, commenting on bookmarks, news, images, videos, knowledge sharing, podcasts and other web pages. Example forms of user input include social bookmarking or direct interaction with the search results such as promoting or demoting results the user feels are more or less relevant to their query.^[6]

Source: http://en.wikipedia.org/wiki/Social_search

Organic search results are listings on search engine results pages that appear because of their relevance to the search terms, as opposed to their being advertisements. In contrast, non-organic search results may include pay per click advertising.

Source: http://en.wikipedia.org/wiki/Organic_search