Thank you for your post!
There does not seem to be a way to share to LinkedIn any longer.
I just shared this post directly with you on LinkedIn. It looks like it worked for me. Do you see the social sharing icons in the upper right of the page (under Return to FileMaker.com)? Try logging out and back into both FileMaker Community and LinkedIn and try again (feel free to send me a direct LinkedIn message to test if you'd like).