In the case of forum games, if it was a thread that only went a few pages and it has been several years since being posted on, its probably better to simply re-make the thread entirely. It can be dependent on the thread though, in the case of forum games the thread owners sometimes request that only they remake the threads or to ask for their permission first (though if the idea is fairly common/not unique that may not always be necessary, its generally good to do so anyway if they are still active). If the thread owner knows someone is interested in playing their forum game they may be fine reviving the thread even if it is a few years old. If you are ever unsure though or don't know if this applies, its also fine to send in a
help ticket to ask site staff if it would be fine to revive a thread or if it should be re-made instead.