"Well, if the broker is being paid by the seller, then that broker is not really representing the interests of the buyer, is he (or she)?"
"A true buyer's broker would be one that the buyer pays."
The law in Canada with respect to agency has evolved (by court decisions) so that a broker can legally represent a buyer and be paid by the seller without compromising the agency principle. All parties must be informed about the true relationship though. FWIW - I work in real estate and this issue is always being discussed given the potential for confusion among the parties involved.