Both, to be fair.
No because he can get away with just scoring goals because that's what he's there for, he couldn't get away with just chasing down defenders and not scoring, at the end of the day we want a striker who can score goals right?, and Yakubu scores goals right?, so i don't know what an earth people are complaining about.
Yakubu may score goals but look where boro are, maybe cos he's lazy and doesnt contribute much elsewhere beside goals is why the rest of the team is carrying him. Look at Rooney or Kuyt or even Drogba to an extent, and others, they track back and defend and help their team out. Just a thought, i may be wrong mind, and boro are just pants.