Hi Joe, sorry for my delay in responding, it's been a busy day today.
Yes when I originally wrote the forum software only the most recent 100 threads could be responded to in each forum. Older threads were closed and moved into an archive and they became read only. Years later we decided to change it so that any thread could now be replied to going back to thread #1. The old "Mark All Threads as Read" button was a viable option then because the database had only to hold 100 records per user. Now with nearly 50,000 possible threads to respond to, holding that many records for each user would put a major strain on the system, so I had to remove it that feature.
And yes we do have a "like" button, it's that red check mark in the upper right hand corner. It was styled after the 1950s Consumer Reports Checkrate mark, when they liked a product they placed that check mark there. I've been thinking lately of labeling the check mark with a term like "applause" or something similar. I'll have to give that some thought as not everyone knows what that means.