It might seem sort of redundant, but I'd love to run a Threads-compatible Guestbook on my site in addition to the message board. I run a fansite, and get tons of surfers just passing through who might be willing to sign a Guestbook to leave a comment, whereas they don't want to go through the entire process of signing up for the message board. Also, I don't really want to have hundreds of signups for my board if they're just folks who want to leave one note, and then they never come back again.
A Guestbook would be a "warm-up" for the shy ones, too. If it had a similar layout to Threads, it might encourage someone to try posting on the board eventually, too.
