Gulliver says, "...my principal Design was to inform, and not to amuse thee." If we take this as Swift, telling us readers what his intent was, of what have they been informed?

This is a pretty open ended question without any concrete answers. Really his intent is open to interpretation. We are assured numerous times that his account is true. The reader thus becomes a little suspicious of Swifts motivations. We know the novel is fiction yet Swift wants us to take it most seriously. I think in the end Swift meant us to treat his account as satire. The reader is meant to be informed about the truth of their own country, specifically England, and their own societal absurdities.