Well, what can we learn from the data? Over the past year, the MOST-popular camera/phone model for Flickr users is the Apple iPhone. It has been #1, and still is #1 for the duration of the graphed period. Following that, the Canon XSi and XTi have been quite popular models among FLicker uploaders. The XSi has remained relatively consistent across the time period. The Nikon D90 has been on a steady, consistent upswing in popularity, as has been the Canon 5D Mark II. So, basically, among the hobbyist-type people and those who like to upload and share their photos via Flickr, the Canon Rebel models XSi and XTi and the Nikon D90 are the MOST-popular d-slr models among frequent uploaders, and the Canon 5D Mark II is also a very popular camera among Flickr users.
I think this information is pretty self-explanatory,and gives a snapshot (pardon the pun) of what the majority of frequent Flickr photo-uploaders are using. The Nikon D90 has been a HUGE, huge success for Nikon, as have the two Rebel models for Canon. The iPhone is the leading "smart phone" and the darling of many techies, yuppies, hipsters, college students, moms, dads, and geeks... The 5D Mark II is a very popular camera with serious photography hobbyists, Strobists, wedding shooters, and regular folks who really like photography.
If you were in the marketing and R&D department of a camera-making company, you might think that this data was very loaded with insights,and might try thinking for a few minutes about what the data is telling you, rather than whining about how useless it is...or asking, "Is this gonna' be on the test?"