You are right, the chart is now spanning 18 months of different maps - I think it might be best to show a rolling 52 weeks?
Be a little flexible in case an important point is just outside this time frame.
And could you please make it a little clearer where the predictions start. For example, there are two predictions represented by green lines, one set of lines starts in March 04 and another set starts in August 04. Although these two sets do not overlap, distictly different colors would make it easier to "read" the graphs. Also, some of the explanatory text overlaps, though, I believe this is because my computer's OS and the browser I use is different from what you are using.
BTW, I was curious about http://www.universalblue.de/, but that page only shows a picture but no link. I assume something is wrong.