OSA vs CIA data gathering.
OSA does not have the same access to web traffic as the CIA/Pentagram does.
OSA can only comb sites of which they are aware and download copies of pages to hard drives and even at that level they are probably in "information overload" most of the time. With the right piece of software (not telling), anyone can download the ENTIRETY of ESMB. Emma would notice the increase in traffic, but little else. With so many off-topic threads, just this one site would result in information overload for some poor OSA hack.
If OSA wanted to find out who was behind the name RPX, they'ld be up a creek without a ladder.
On the other hand, CIA/NSA/Pentagram etc. can lock down one IP address and capture EVERYTHING sent or received by that computer. Again information overload and staff incompetence are on our side as they sift through people's shopping lists to find the stuff they really want.
If the MIC (Military Industrial Complex) wanted to ID me, then they probably already have, right down to full name, street address and telephone number. BUT, what has my puny little self done that would warrant their attention?