I think a lot folks think "suspect" when someone signs up to the site simply to post a For Sale ad with nothing but pics. It's a lot easier to trust someone when they've been here contributing to the group for a while. Not criticizing just pointing out why it was brought up.
And why should someone have to go from here to IG to get details? You signed up for the site to try and sell your vehicle so, just a friendly suggestion, try and sell it here. Or is posting what kind of engine, transmission, trim level, etc, too much work?