The site is obviously in progress, with very limited coverage. The author uses a non-standard notation for displacement (d). The discussion on how to construct graphs is promised, but still missing.
General Comments on Quality: What is here is physically correct, but very limited. The two VRML applets show only uniform motion and speeding up at a constant rate, and are not worth the effort to download the plugin. The ability to move and rotate the graph adds little to the presentation. A simple java applet or even an animated gif would do the same with less chance of technical problems. The tutorial discussion, though good, is limited to the relationships between position and constant velocity graphs, and velocity and constant acceleration graphs. There is no discussion of the slope of curved graphs or the area under anything but constant value graphs. The organization of the material seems non-optimal. For example, the order of section 3 and 4 should probably be swapped. The XVA Kinematics Graphs tool is excellent for those who wish to develop tutorial material, but is used only sparingly.