Why many companies only register either one? .IN or .co.In

[chrome]

If a company only registered a domain like twitter.in
Should I register the .co.in domain like twitter.co.in

 

[pubdomains.in]

If you are serious about developing your site and don't wish to lose out on traffic after you have done all the hardwork - go for all, don't just stop yourself at .in or .co.in

Your statement in title - is incorrect, typically companies register all extensions, while individuals (domainers) invest only in one or two extensions looking to sell them in future at a premium.

 

[Ceres]

If a company only registered a domain like twitter.in
Should I register the .co.in domain like twitter.co.in

If it's a well-known trademark, my advice is to stay away from other domain extensions.

If there's no registered trademark or common law rights attached to the term, then it's okay to register the name in another extension.

For more info, see this thread.

 

[Jeff]

I've noticed this too - a lot of companies seem to register their .in domain and not worry about their .co.in domain. Very short sighted IMHO.