You can try regular share plugins for WordPress. They should be loaded on forums and topics.

Thank you for your reply.

I have tried ultimate social deux and jetpack social share buttons, they didn't work.

Do have any one that you have tried and it worked?

I'm also looking for this. It is a key feature to try to bring in users from external social media.

I bet they create a social media add-on. But, it would be nice to find a current Wordpress plugin that works. I think the problem is, all or most of the Wordpress social sharing plugins, are coded to work with the default post type and page type. WP Foro uses a different post type I believe. It's not obvious what it is either. Maybe I'll do some digging in the code one of these days.