Is a domain registrar, such as goDaddy, always also the hosting service, or are there any companies that just register domain names? Would a company that only registered domains be able to remain in business?
Yes, there are many companies that have started by offering domain names only. But since domain names are so closed and related to hosting, those companies would not be very money wise not to offer hosting as well.
Saying this I'm thinking about Enom, Name.com, NameCheap, etc
Years ago, the markup on domains was anywhere from 400% and higher. Domains were being sold from $35/year and $70/year in many cases. These days with domains being sold as low as $8/year and the actual FEE ICANN charges is $6.95 there's so little markup that domain registrars have all pretty much turned to hosting, ssl certificates and other sources to suplement their income.
Indeed under the modern IT industry,many companies are finding the opportunity to make money or considering to expand their current services market. So as more and more domains are needed then hosting plans comes to their mind.
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No, domain registrars do NOT equal hosting providers, although they can be. And I wouldn't take any free domain offers tied to hosting because you'll encounter real issues transferring that domain should you switch hosting providers.
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