I have just had a couple of text alerts that people I know have "sent [me] a message on Zee..." that I can view by clicking a URL on the zeechat.me domain.
I haven't, of course, since these people were far more likely to text, phone, or email if they wanted to contact me.
Zee appears to be a chat app for Apple and Android - one of my contacts got a similar message and installed it, and it seems to have spammed his contact list. The chain reaction sparked a second one from a mutual contact within 10 minutes. At least one other mutual contact got the same two messages and had the sense to ignore them.
So if you don't want your contacts spammed, ignore any of these alerts