Marketing = analysing and serving a market. SN is doing a lot of this, carefully assessing new features and soliciting user feedback.

Promotion = advertising and comms to bring in new users. They're also doing this, largely in Bitcoin spaces and fairly quietly. Seems sensible for now as it's best to carefully grow discussion communities. Scaling too fast brings moderation and culture issues.

The real question in marketing terms is assessing the current user base and how they're served vs the future expected user base and what might serve them.