do users want it? no. do users not want it? also, for the most part, no. people don't care about this nearly as much as you want them to.
fully informed and knowledgeable people can make a decision that they don't really mind if advertisers know a bit about them. especially when it's as benign as knowing what general topics they might be interested in.
This reads like "only tell people who ask, exploit those we can get away with, and when they start to catch onto our schemes, obfuscate the system by adding new complexity and telling them it's for their own good, then repeat."
fully informed and knowledgeable people can make a decision that they don't really mind if advertisers know a bit about them. especially when it's as benign as knowing what general topics they might be interested in.