I recently added a new feature, which is now live on OGS, that lets you conveniently link to a particular move number in a game by appending it to the game url, e.g. https://online-go.com/game/425048/92 will skip to move 92 in that game when you open it. Hopefully you find this useful when sharing links to particular moments in games in forums, chat or social media e.g. to ask for help with a particular position or sharing a move you are proud of.
One thing which isn’t working yet is using them in the OGS chat rooms (one of my main use cases!): the usually helpful game link shortcut formatter ends up breaking them, so that’s on my to-do list to fix.
P.S. internet cookies to whoever recognises the very cool tesuji of my example link