[mmatey]

It's an interesting visualization, but thumbnails of the sites for HN links just don't seem that powerful to me.

The power of a HN post is the text.

If you could implement something like what Arek is asking that would help.. maybe change the background of the tile from blue to red depending on the popularity?

[heliostatic]

Color is a good thought. I was thinking about using sparklines to show activity over time inline, but color might be simpler and more arresting.