But the resources of government will always be large enough to find everyone. For example, whenever there is some cyber-attack, within days there is at least a suspect, whether he, usually he, is convicted.
The resources of the NSA, already in the billions of dollars, will only get bigger.
One of the more prominent of the pseudonymity companies, zeroknowledge.com has a specific disclaimer for the actions of a government, or other, large intelligence organization.
In recent weeks, the Government of Canada was caught with a database with up to 2,000 records of information on each Canadian. It was only after days of political pressure that the Minister responsible reversed her position, and ordered the deleting of the database. However, the source databases will continue to exist. It was called, I believe, the Longitudinal Labour Fource Survey.
And this doesn't consider Project Echelon, and the UKUSA agreement.