Backlinks are links that point to a webpage or a website. These in essence determine the popularity level of a website. A search engine ranks websites in order of popularity and importance. This depends on the density of keywords that are searched for in the website’s content, URL, etc . Search engines also rank websites based on thequantity of backlinks that a website has. Hence, one aspect of search engine optimisation for a website is increasing the number of backlinks. This is what any SEO expert will tell you to start with. However, it is both quantity and quality that help increase a website’s listings. There are two main factors that determine the quality of a backlink – The backlink should be similar to the webpage, at least in terms of the theme and the backlink should link to the website because of the keyword. Therefore, while building backlinks to a webpage to optimise its search, it is important to keep in mind that the contents of the back-linking site must not be identical, but similar. However, too many backlinks to a website can prove to be counter-productive. In a day, if there are more than hundred to two hundred backlinks to a website, particularly of low quality, the website’s ranking will be adversely affected and in extreme cases, can lead to de-indexing of the site.