Search indexing content online: Func­tion­al­ity and op­tim­isa­tion

Google and other search engines index online content so it can be displayed to Internet users in search engine results. Search engine op­tim­isa­tion is essential as it enables other machines and Internet users to find online content.

Search indexing predates the Internet and describes the practice of compiling data. Archives and libraries regularly use search indexing, whereby keywords which reflect the topic of a document are assigned. Users or visitors can then easily source material by entering a keyword into the database, for example, an author’s name, a year, or a specific title, which will result in the index showing the items which cor­res­pond to the keyword. It works similarly on the Internet.

Search engines such as Google operate on a similar principle to an archive’s or library’s index. When a user enters a keyword into a search engine, the index will be searched and show the results it finds in a specific order.

Indexing is made possible through online tools. Search engines use crawlers or search bots to scan the Internet, visit new websites, analyse their content, assign keywords, and add it to the search engine’s index. This means that text documents and their updates, as well as images, videos, and other file formats are all being captured by crawlers.

Since there is so much content for the same keywords nowadays, the search results are presented to users in a specific order. Websites are ranked and the content which is most likely to be relevant to the user appears first on their list of results. Google Ranking Factors determine which content is most relevant for a search result. Many of these factors are known, but the weighting is not always clear and is also fre­quently changed by the search engines. However, giving the user the best possible ex­per­i­ence is always the goal.

Websites must be indexed by search for users to be able to access their content. However, just indexing is not always enough given the huge volume of web content available these days. Search engine op­tim­isa­tion is crucial to ensure that a website is properly indexed and ranks as highly as possible in the relevant searches. But what exactly is meant by op­tim­isa­tion?

In the early days of search engines, it sometimes took several days or weeks for a crawler to discover and index a new page. To speed up this process, it was possible to register a website directly with Google. Thank­fully, this is no longer necessary as the search bots are now con­stantly crawling and indexing new content quickly.

Nev­er­the­less, website operators can and should support crawlers in fully indexing the relevant content. For example, it is a good idea to register for the Google Search Console (formerly: Google Webmaster Tools) and create a sitemap with the relevant pages and subpages. The robots.txt file indicates to the crawlers which in­form­a­tion, pages, file types, and dir­ect­or­ies should be excluded from the search and indexing. In­di­vidu­al pages can also be excluded through the noindex tag.

There are other commands which can be placed in the header of a website, which provide the crawler with important in­form­a­tion, such as which version is the original in case of du­plic­ates (canonical tag).

Web content should always be fully optimised so the website can place in the top rankings on Google. Op­tim­ising texts for keywords and meta data, i.e. the title and the de­scrip­tion, which are the displayed search result, should be completed in ac­cord­ance with known spe­cific­a­tions. Internal and external links, struc­tur­ing of content, as­sign­ment of file names etc. belong to the long list of steps which are important in search engine op­tim­isa­tion.