Link Exchanges
Link Exchanging is the process of exchanging text links or banner links between websites. Webmasters exchange links to improve traffic through numerous inbound links so users on other websites can click through. Exchanging links is normally a free process (unless you choose to use a link exchange program which charges fees), making link exchanges cost effective. Another benefit of using a link exchange service is that it helps improve placement in the search engines. Link exchanges have been used by webmasters for years as a means of direct marketing. Recently, this practice has gained more popularity among webmasters due to the fact search engines prefer websites that have many inbound links, thus improving positions in the Search Engine Result Pages (SERPs). To the search engines, this is an accurate means of determining the importance of websites. This practice by the search engines to rank websites has helped lead to the popularity of linked-based search engines, like Google. Thus, link exchange software and services have become popular. There are various ways to initiate a link exchange with another website. The primary way of beginning a link exchange is to email another webmaster and ask to exchange links. Another way to find websites looking to exchange links is to visit webmaster discussion boards. These websites might have link exchange forums or link exchange directories where webmasters can request link exchanges from a specific category or have open requests to allow any website to exchange a link. With the importance of link exchanges, many types of link exchange websites have emerged as a source for webmasters. There are 2 types of link exchange directories. Paid directories make the process of exchanging links easier, but cost money and usually require software to be placed on the webmasters website to assist with the link exchange. Free link exchange directories have no cost, except they require the webmaster to manually add each website. Webmasters can have complete control over links when part of a free link exchange. Recently some marketing companies have stated that search engines are no longer placing a heavy importance on reciprocal links. The consensus is that popularity of a website is now gauged by incoming one way links. The experts also agree that in addition to having numerous inbound links, the relevance of the linking websites is very important. Link exchanges between complimenting websites is important. Webmasters do not have to link directly with competitors, but should link with websites that have industry relevance. Having a website link with no relevance could potentially negatively affect Search Engine Result Pages. Websites that have completed many link exchanges will usually experience increased traffic through direct clicks and search engine results. There are various ways for webmasters to find linking websites through direct email contact or link exchange directories. It is important for webmasters to check the relevancy of the links that are being adding as links that have little or no relevance might negatively affect their placement. The use of link exchanges by webmasters will continue to be an important and useful means of marketing websites and improving search engine placement. 
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Mathematical PageRanks (out of 100) for a simple network (PageRanks reported by google are rescaled logarithmically). Page C has a higher PageRank than Page E, even though it has fewer links to it: the link it has is much higher valued. A web surfer who chooses a random link on every page (but with 15% likelihood jumps to a random page on the whole web) is going to be on Page E for 8.1% of the time. (The 15% likelihood of jumping to an arbitrary page corresponds to a damping factor of 85%.) Without damping, all web surfers would eventually end up on Pages A, B, or C, and all other pages would have PageRank zero. Page A is assumed to link to all pages in the web, because it has no outgoing links.
Pagerank
PageRank is a link analysis algorithm that 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 also called the PageRank of E and denoted by PR(E). PageRank was developed at Stanford University by Larry Page (hence the name Page-Rank[1]) and later Sergey Brin as part of a research project about a new kind of search engine. The project started in 1995 and led to a functional prototype, named Google, in 1998. Shortly after, Page and Brin founded Google Inc. , the company behind the Google search engine. While just one of many factors which determine the ranking of Google search results, PageRank continues to provide the basis for all of Google’s web search tools.[2] The name PageRank is a trademark of Google. The PageRank process has been patented (U.S. Patent 6,285,999 
