The conversation a post can start

A friend shares a photograph from a walk. You recognise part of the route, ask where they turned off, and send a message about going together next weekend. A small update has given you a reason to talk and something to do together.

That is a good outcome for social media. The post offered an opening into another person's life. Replies let you take an interest in what they shared; messages give you somewhere to continue when the conversation becomes more personal or practical.

TouchGrass includes both because an update should be easy to respond to. A question can stay with the post so other people in its audience can join in. A direct message can carry on the exchange between the people involved. These are familiar tools, and their familiarity helps: you can get on with the conversation.

We judge them by whether they help people keep in touch. A reply that becomes a plan to meet has done something useful, however modest the original post was. That gives us a better reason to build conversation features than trying to increase the number of interactions on a dashboard.