|The Community Hub card
There is a reserved card with the text 'community hub' on each server. Click the icon in the top-left corner of the screen to visit this card.
Drop any card onto the hub icon (an icon of a sun, by default) to send it to the priorities list of the community hub card. A badge on the hub icon shows the current number of priorities in the hub card.
Having one card as a shared starting-place for everyone makes it much easier to start sharing cards, memes, and news in smaller communities. The other way to share stuff within a server is guilds.