I presume it would be technically achievable to allow report writers to PM fellow users on Adultwork to ask for further info on a potential booking.
Do you mean like an instant chat/messenger service, where one could add in 'trusted members', who wish to share information on a certain SP? As far as I'm concerned, with the way the site is currently constituted, I prefer to share my via PM only.
I don't wish any prossie to read my personal recommendations or info on other SPs. I don't believe they're entitled to read that and I don't consider it any of their business. I share my info to help other punters, not them and for a prossie to have access to personal information on another SP, could represent a major conflict of interest. Add to that, the potential trolls and troublemakers too, who aren't genuine punters.
An instant chat facility would be good, when talking about sharing recommendations and seeking more detailed info.