The way humans see a website is different from how Search Engines see it. Same appearance of a website can be achieved by using different coding methods and strategies. Sometimes a website is very user friendly but the coding strategy used to build the website is complex which makes its content confusing for search engines.
Source Code Optimization is done to make it easy for the Search Engine crawlers to find, read and index a website. In other words Source Code Optimization makes a website search engine friendly. A Search Engine friendly website makes it easier for the search engine to locate and read the content of a website just like a user friendly website makes it easier for a user to locate and read the important and relevant information.
As Search Engines don't see a website the way humans can see it so, even a minor technical issue can mislead them. In Source Code Optimization technical issues that can make the website content too complex for the Search Engines are located and removed. By the help of Source Code optimization the code of a website if organized to categorize the website content as per its importance and relevance. Content Placeholders are defined according to the type of content that they have to contain and they are properly linked together to maintain a relationship of content throughout the website according to the relevancy which helps search engines to easily locate relevant data throughout the website and easily locate the content relevant to a certain topic.