Move down all posts in your columns simultaneously, with a single key stroke! In other words, PageDown adds the ability to use hotkeys to *page down/up* all of your Mastodon columns in the Advanced Web UI (if you are using that setting).
The extension that is in the Chrome and Firefox store works on the top ~40 servers. See below for the complete list of servers.
(Aside: Why this approach? Because I wanted to avoid publishing an extension in the stores that asked users for permission to read *all data on all sites*. This way it doesn't, but that meant making a list.)
"*://mastodon.social/*",
"*://*.mastodon.social/*",
"*://journa.host/*",
"*://*.journa.host/*",
"*://pawoo.net/*",
"*://*.pawoo.net/*",
"*://baraag.net/*",
"*://*.baraag.net/*",
"*://mstdn.jp/*",
"*://*.mstdn.jp/*",
"*://*.mastodon.cloud/*",
"*://mastodon.cloud/*",
"*://*.mstdn.social/*",
"*://mstdn.social/*",
"*://*.mastodon.online/*",
"*://mastodon.online/*",
"*://*.mas.to/*",
"*://mas.to/*",
"*://*.mastodon.world/*",
"*://mastodon.world/*",
"*://*.sdf.org/*",
"*://sdf.org/*",
"*://*.c.im/*",
"*://c.im/*",
"*://*.mastodon.uno/*",
"*://mastodon.uno/*",
"*://*.mastodonapp.uk/*",
"*://mastodonapp.uk/*",
"*://*.fosstodon.org/*",
"*://fosstodon.org/*",
"*://*.universeodon.com/*",
"*://universeodon.com/*",
"*://*.mastodon.top/*",
"*://mastodon.top/*",
"*://*.techhub.social/*",
"*://techhub.social/*",
"*://*.mstdn.party/*",
"*://mstdn.party/*",
"*://*.mastodon.art/*",
"*://mastodon.art/*",
"*://*.infosec.exchange/*",
"*://infosec.exchange/*",
"*://*.ohai.social/*",
"*://ohai.social/*",
"*://*.masto.ai/*",
"*://masto.ai/*",
"*://*.sfba.social/*",
"*://sfba.social/*",
"*://*.mastodon.scot/*",
"*://mastodon.scot/*",
"*://*.mastodon.nl/*",
"*://mastodon.nl/*",
"*://*.mastodon.xyz/*",
"*://mastodon.xyz/*",
"*://*.mastodon.technology/*",
"*://mastodon.technology/*",
"*://*.aus.social/*",
"*://aus.social/*",
"*://*.mindly.social/*",
"*://mindly.social/*",
"*://*.home.social/*",
"*://home.social/*",
"*://*.toot.community/*",
"*://toot.community/*",
"*://*.hachyderm.io/*",
"*://hachyderm.io/*",
"*://*.nerdculture.de/*",
"*://nerdculture.de/*",
"*://*.ioc.exchange/*",
"*://ioc.exchange/*",
"*://*.gamedev.place/*",
"*://gamedev.place/*",
"*://*.mastodon.au/*",
"*://mastodon.au/*",
"*://*.ravenation.club/*",
"*://ravenation.club/*",
"*://*.newsie.social/*",
"*://newsie.social/*",
"*://*.chaos.social/*",
"*://chaos.social/*",
"*://*.linux.pizza/*",
"*://linux.pizza/*",
"*://*.indieweb.social/*",
"*://indieweb.social/*",
"*://*.vivaldi.net/*",
"*://vivaldi.net/*",
"*://*.econtwitter.net/*",
"*://econtwitter.net/*",
"*://*.fediscience.org/*",
"*://fediscience.org/*",
"*://*.twit.social/*",
"*://twit.social/*",
"*://*.mstdn.party/*",
"*://mstdn.party/*",
"*://*.ruby.social/*",
"*://*.phpc.social/*",
"*://*.medievalist.masto.host/*",
"*://*.mstdn.games/*",
"*://*.peoplemaking.games/explore*",
"*://*.gensokyo.social/*",
"*://*.socel.net/*",
"*://*.elekk.xyz/*",
"*://ruby.social/*",
"*://phpc.social/*",
"*://medievalist.masto.host/*",
"*://mstdn.games/*",
"*://peoplemaking.games/explore*",
"*://gensokyo.social/*",
"*://socel.net/*",
"*://elekk.xyz/*",
"*://tech.lgbt/*",
"*://*.tech.lgbt/*"