Creators continue finding ways to use digital comics that print can't replicate. The new "Click and Drag" strip at xkcd invites readers to do exactly what the title suggests as they navigate their way around an enormous world of silhouetted landscapes and stick-figure people having adventures and quiet moments alike. It's an amazing, immersive, very time-consuming, but rewarding experience to explore the whole thing.
For those less patient, there's also a version that shows the whole world at once and lets readers zoom in and out, moving more quickly. It's faster, but it loses the aspect of discovery that clicking and dragging across a confined panel has. I recommend spending as much time as you can clicking and dragging (be sure to go down holes; there's more underground!), then use the big map to go back and see what you missed.