When looking at my account on the website, specifically how much data my various devices have used this month (e.g. at https://ting.com/iaccount/current_megabytes), it shows a list of how much data each device used each day. It's possible to filter by a single device, but there's still sometimes multiple entries per device per day; my wife's phone, for example, has 3 entries for data used on Feb 01 (1.18, 629.80, 25.64). What would really be nice is a chart that showed vertical bars for total by day, and even could do stacked bars to show multiple devices on the same day. Or, at the very least, the ability to CSV export the data so that I could process it myself; currently I have to literally copy and paste (and deal with weird formatting), which is not helpful at all.
Data usage visualization