I've gotten my visualization code almost 100% working for the master branch after much effort and adjustment of the 1.0 visualization code (many thanks). So I wanted to do a comparison with your "canon" BrightKite sample to make sure that everything was displaying the correct information.
Aside from a minor problem with the way I dumped the 'Day of Week,' everything matches up, except that my time-series is very jagged in comparison to yours. The shape is similar, but yours is much smoother. If I pick a single day on mine (Sunday for example), then I get a series of equally spaced peaks with nothing in between them, which makes sense since there would be no data for the days not Sunday. If I select a single day on your sample, the time-series barely changes, very smooth and essentially the same shape.
I took a screenshot of a comparison between the two to show what I mean, but it didn't go through here.
I'm curious if you guys have any ideas about why the time-series would be so jagged.