Much, much, earlier if you squint a little. 1998.

http://infolab.stanford.edu/~backrub/google.html

"The Anatomy of a Large-Scale Hypertextual Web Search Engine"

-> "Appendix A: Advertising and Mixed Motives"

-> "The goals of the advertising business model do not always correspond to providing quality search to users."

Not browser specific, but they understood the problem well.