Someone enterprising could do a great service to this community by setting up code to gather all publicly available upgrade stats before each flight. Thanks to online upgrade lists at united.com and mobile.united.com , if we check just after the flight has closed, we could have a database with the following:
1) date
2) day of the week (follows from 1)
3) flight number
4) origin
5) destination
6) aircraft
7) number of total C or F seats (follows from 6)
8) number of people upgraded (number of checkmarks)
9) number of people booked into F or C with revenue, miles, or upsells (not upgraders, 7 minus 8?)
10) number of people on the waitlist at departure
This database would be quite helpful for planning purposes. Just knowing the percentage of upgraders on each flight would be fascinating. Sure, it would be great to know the status and booking class of the first person on the waiting list at each departure, but this database would be far more exhaustive and representative than udustats even if the question it answers isn't complete.