Any one can now have their own websites or at least blog sites to share his or her thought on various fields of their interests. People either as individuals or as organizations can buy a domain to do this or at least can have a sub domain of the main domain of a website and this is the first step towards creation of websites.
At the same time, particularly companies and organizations that wish to create a website for their commercial purposes cannot comprise on the domain names of their websites as most of them wanted to have their company names as their domain name too.
So. if a company wanted to have a domain which was already taken up still by using domain name availability, a free service offered by popular web hosting sites they can still check if the same name can be used with a different extension. This has led to the creation of websites with same names but with different extensions.