Ketones and nucleophilicity
Everyone says something different


Well, actually they don't. A ketone has a nucleophilic and an electrophilic center. The carbonyl carbon is electrophilic and can be attacked by nucleophiles, the oxygen itself can act as a nucleophile and can, for example, be protonated. And yes, if we protonate the oxygen the "ketone", or better the carbonyl carbon, get's more electrophilic.

An example would be the Luche reduction. In this case the carbonyl oxygen coordinates to cerium chloride, thus acting as nucleophile, and makes the carbonyl carbon even more reactive towards nucleophiles.