Often when registering your domain, you need to choose from a range of Top-Level Domains (TLDs). To put it in layman term, it refers to the suffix attached to domain names.

For instance, the TLD for example.com is .com. The TLD for example.net is .net.

Because of technical issues and others, during the last few years, ICANN started to introduce new TLDs specifically for many industries.

Also don’t forget there are country specific TLDs, like .uk for United Kingdom and .us for United States.

Basically, AdSense publishers are allowed to choose from any top level domain, except perhaps .xxx, which are going to be approved for online adult entertainment. As long as you comply with Google AdSense Program Policies, you are safe.

There are many other considerations though when starting your new site.

A .biz domain is for business purpose, but it may trigger spam filter if you are going to adopt email marketing as part of your marketing strategies, using the domain in question.

Generally, .com domains are so common that people think when you own a website, you own a .com. It is common sense. When you see an online ad, you expect it to be whatever-the-company-name-or-brand dot-com. It may be of your benefit to have a .com for this case.

For me, I always choose .com when registering for a new domain. They may say all good names have been taken, but really if you let creativity kicks in, you can still get great domains.

I often get very good deals on .info domains too. But your mileage may vary.

You can get a complete list of TLDs from ICANN — International Corporation for Assigned Names and Numbers.