Right now everyone's digital communications are being collected by those agencies, via fiber optic cable taps [1]. This could be called bulk surveillance. Different people & groups have access to these databases of communications. Some are government employees, some are contractors. Now, what if an activist or a Senator starts speaking out against bulk surveillance? Would those with access to the databases be tempted to run a few queries?
'SELECT * FROM `sms` WHERE `person_id`="$senator_id"'
Note: Most analysts would never run that query. But it just takes one.[1] http://www.pbs.org/wgbh/pages/frontline/homefront/interviews...