Stickied rbitcoin threads
The subreddit r/bitcoin is one of the largest bitcoin communities on the internet. As of September 2018 it has more than 900,000 subscribers.
Since around Late 2017 the moderators have stickied selected threads to the top of the forum.
Note that sometimes threads are unstickied and then stickied again, so the date stickied cant be used to find the duration the thread was up. Archive links alongside are preferable as backups. This list may be incomplete.