Families and domestic/SoHo etc
VM ntlworld emails are likely to be small users, not technically very aware and relying on the email that the ISP supplies. After all Email is Email to most ordinary users and all that matters is that they have a nice name to use.
Commetards on El reg will have multiple adresses, mail servers, disposable accounts and all that stuff. But not the gen pub.
And even many of the commentardists may still use an ISP account for family and friends email, or ordering from Amazon etc.