Consider whether you want just Chinese numerals, or also Arabic (normal) numerals in the corner.

Consider which style of mahjong it will be used for. Depending on the style, there are different numbers of total tiles included in the set.

The feel of the tiles might matter to you, but unfortunately that may be difficult to judge when buying online.

I just hope federal services (like applying for a passport) don’t become Twitter-only after Trump appoints Elon as Secretary of Enshittification.

Just about anything. IRC, XMPP, Discord, whatever you call the chat built into Steam. AIM is discontinued now, but it used to be better than Teams is today.