Would we know? He's already here. I'm quite sure the NSA is here ;)
I would hope that President would have more important things to do than to sit around on Blurtit at all day. :)
If it was the POTUS, he'd probably ramble on about global warming.
With all the anonymous, we may already have one.
I would feel normal and i would think it's their personal choice and it would be okay if they wanted to join.
Today's world is technology/network and communication. For instance even U.S military have Facebook account and updating about training,missions and it's events and conditions and technologies and each detail.
Presidents having social media account such as facebook and twitter for updating and communicating and giving confirmation by themselves through different occasions and rumors. Even in countries that network is not easily available and citizens need to pass a filter or kind of a proxy codec to access full network. Their presidents and leaders own full access to network and having social media accounts for this usage.
Blurtit would be a site like any of these accounts. It's even greater as it's could be consider more personal and individual. (As facebook or twitter accounts can run by agents and people charged by owner's account to post instead) also owning such an account doesn't mean you have to be out of life,work and activity to be here. Presidents can easily be here share their opinion to different questions or ask questions and opinions of people directly. And nobody knows, people in presidential chargers can also be involve under different identities and unknown terms and involve in such sites due different purposes and aspects. Seeing president in such sites is not odd at all. Not in today's world and communication importance and role.
Like, Wow. That's amazing.