"Oh, I just marked you/everyone to see if you had marked me, I wasn't being serious."
The first observation was the glaring red making me turn away from the app. Interesting idea, but what's to prevent people from selecting everyone--just for fun?
Both the red/white color scheme, as well with the "+" in the logo/favicon, don't exactly have the best connotations.
I don't see how this is different than just asking someone within a message.
My first ever app. Feedbacks are much appreciated.
The red really hurt my eyes (on an iPad). Otherwise, congrats on the launch.