^^^^ A year or three ago a long time member went sort of ... bonkers ... necro-posting vacuous addenda to a great many long-silent threads. In addition to getting banned, he caused the mods / admins to lock inactive threads to avoid more of this. If you have something relevant to add to a locked thread, pm the admins / mods and they'll re-open the thread for you. It's not a detriment to engagement or a problem for serious researchers unless they are just too lazy to send a PM and too impatient to wait for our overworked VOLUNTEER staff to take care of it.
MIB