There are many theories about this: Google's algorithms, however, remain a mystery. According to some, Google will rank your site based on its content, while others state that Google will also look at the TLD. Be that as it may, choosing an extension for your website is not something you want to take lightly. If you opt for a lesser known domain extension, visitors or customers may not trust your site. That is also why it is best to avoid certain extensions for your domain name: because they are often used by spam sites.