He didn't. That's another one of the baseless myths trumpeted to keep this whole silly issue going.
The Executive Order you're referring to (13489) deals with the process of how “Presidential Records” (i.e., records generated while one is President) are archived and accessed. Basically, it lifted the more restrictive access protocols imposed by Bush II, restoring the process to approximately what Reagan established when he was in office. It has absolutely nothing to do with Obama’s personal records before he was President, and is not even particularly interesting.
I disagree. The way it is written, it gives him authority to claim executive privilege on any records at his whim.
I believe he did just this for just about all his educational records, and possibly his BC.
The EO under Bush was more restrictive, in that it restricted what the President could contend was 'executive privilege', while (as you state) the Obama EO is much less 'limiting'.