Hello Jan,
Thank you for this very useful site. I have used it for a long time and I have always found it very helpful. One of those "does one thing and does it well" websites.
I've had just one idea for a slight improvement that I wanted to share with you:
You know how when you mouse hover over the data points, it gives you a little more information? I thought it would be useful when hovering over the yellow "block" data points if it could give you the block number of that new block. For both the blue transaction points and the red trade points, it gives you some quite useful extra information with the mouse hover. The yellow block hovers don't really tell you anything useful, except that 50 new bitcoins were generated, which we probably already know. As far as I can tell, there is currently no way to gather the current block count from your site. You probably already have the data to make this small change, it would make your chart slightly more useful, and would save everybody the trouble of opening yet another page to get the current block count. Of course there are other sites to see the current block count, but sometimes I would find it useful to see visually when a certain block number was generated.
Just my 2 bitcents...
Thanks again and I love your site.