Why do I sometimes get text messages from an Apple ID instead of a cell #?

[iMore Question]

always from an iPhone, always from someone I have in my contacts, but instead of coming up text from: "whomever" or a phone number - it's from their apple id? It's very odd.

 

[kch50428]

Because that person has elected to start conversations from their iCloud email address instead of phone number on a device.