Mobile Phone Sign Ups


Hi All

I’ve got an on demand service in production at the moment and deciding whether to launch with a mobile app or simply ‘text to deliver’.

My question is:

Has anyone tested or can direct me to case studies on whether it’s better to ask for email address or mobile phone number on sign up? (if that is my only call to action)

I’m seeing more and more sites using ‘text me download link’ buttons (which asks for the users mobile number) on their site instead of asking for an email address.

Any thoughts will be well received.