Planning for lazy users

While interactivity is fun and cool and popular and etc, you need to assume your reader will not click or hover. You should generally make your visualization meaningful or interesting without forcing interaction. Interaction should be a bonus.

Adding text annotations or starting your visualization from a post-interaction state are two simple ways of solving this problem.

Tell a story

Your visualization should always have a message. Your job is to curate the data that is being presented to the user; putting down 500 points on a scatterplot or 100 lines on a map and telling users to interact is not good enough.

While the explanation vs exploration spectrum is totally valid, users will usually only want to explore your data once you're hooked them.