That would've been fantastic to see those that are online. I've been thinking about this for a while now because there are times I am online, I will feel I am the only one that's here. It would be a nice to see those who are online if possible be able to strike a conversation with them.
Nonetheless, I think the owners of answeree don't want a situation whereby members would be engaging in trivial conversations that has absolutely nothing to do with the purpose of the site, which is q&a. We all know how some of us could get if chat segment was created. Some might decide to be straying from the objective of why they are here.
I think if they thought it would be helpful, they would have taken it into consideration, just as it is with Freelancer website. On Freelancer website, the chat segment is important as it enables the employers to communicate with members on the site if they want to give them jobs. But in here, I don't think there would be need for all that since nobody is in need of the other members services.