That infuriated me last year when I finally tried to create a Twitter account.

During registration I was given a choice between providing an email address or a phone number. I provided an email address, only to immediately have my account locked until I provided a phone number. Well, I wouldn't have given my email address if I knew a phone number was required anyway! It wouldn't even let me visit my account settings to delete my account, and I never got a reply when I emailed Twitter support.

I had a similar experience. In my case they allowed my account to be opened without a phone number as I requested that they delete the account because I didn't want to provide my phone number. I deleted my account soon afterward anyway.

That's pretty interesting. I've had a twitter account that has no phone number and no email for a very long time. It's never been blocked.

If you've had the account for very long it's probably grandfathered.

Be careful, my 10 year old account was permanently suspended without warning and support is no help; I suspect it's because I didn't have a phone number on my profile.

I had one account that got locked because of that and it took a lot of digging to find the right support link, but eventually I made a support request saying I didn't want to give them my phone number and violate my privacy and they finally unlocked that account. It wasn't easy though.