Remember that not all of that 53% knew what they were voting for. They fall into that gray area in the middle; the uninformed, apathetic masses.
They followed a guy who read speeches really well and looked like a fresh change from Bush. In fact, many have said that the 2008 election was pure Bush-backlash.
So no, 53% did not vote for socialism.
He really never pretended to be anything different.