At a talk given at the TU Munich, somebody asked Jacob Appelbaum why he (the questioning party)
should care about privacy at all. I routinely ticked off a list of possible answers, but
Jacob had a new one (to me): (quoted from memory)
So you're doing nothing illegal, why should you worry about privacy?
Well, in the
late 40ies there were people who were thinking about the possibility of changing
the political landscape of the US. They visited lectures, read papers and pamphlets etc,
everything totally legal. Yet a few years later they were accused of being communists
and were fired. Because they did something totally acceptable a few years earlier.
In the 90ies there were Muslim families in the US who followed the custom of donating
to foreign aid organisations. A few years later those organisations were decreed to
be aiding terrorists and therefore everybody giving them money in the past is now
a criminal. Because they did something totally acceptable a few years earlier.
And who knows what totally acceptable deed now will be illegal post hoc tomorrow.
The accumulated history of past behaviour can be used anytime in the future to
discredit or accuse. And the accusing party can filter the data for damning evidence,
whereas the accused has no access to the data to find exonerating evidence in it.
So history teaches us that everybody should have very strong objections against
a secret store of every word they ever muttered online.
In Germany, it is a felony to be member of a criminal organisation. That an
existing organisation has criminal purposes can only be decided after somebody
joined it. So this definition of a criminal act by being a member of some organisation
implies the post hoc for at least some members.