No mate, the y-axis stands for the DAILY TRAFFIC RANK and not the traffic...so as far as i know, lower the left y axis, lower is the rank of DP(daily)
It's likely going down because of all the database problems. Some days I can't get on for hours at a time and when I do, it takes 10 minutes to load a page.
I would find it interesting if the traffic was going down, I think this forum is quite busy, interesting informative and a great place to do business.