I wonder how can we grab register.com expiring domain names. I see that the owner has let go a domain name but register.com extended it.

Does register.com follow the pool and netsol practice where they grab expired domain names and put it for auction?

Register.com has partnership with Snapnames at the moment and you can get expired domains through Snapnames. They will be able to grab it, before it is deleted and available to the public.

snapnames has deals with most of the larger registrars

register.com, nsi, bulkregister etc