Yes, in a variety of ways. All marks currently support native tooltips (the title channel), and in the near future we’ll be releasing more interactions that you can compose into the chart, e.g. for brushing or pointing. As I mentioned in another comment here, Plot is designed to leverage Observable’s language-level interactivity (dataflow) — so all plots are reactive by default, and plots can expose an interactive selection to the rest of the notebook.
I'd love to use something like Plot or Vega but this is exactly why I am still using D3. Zoom, Delaunay tooltips, and extensible interactivity that I can get to work well in a React based application are very important. Unfortunately Vega's solution to anything interactive seemed incredibly awkward to me at the time.
The only time it seemed like Vega made sense was publication style graphics which was unfortunate.
