you obtain the necessary warrant and then perform whatever action is necessary without breaking the law. was that so hard?
No it shouldn't be. As long as the businesses keep the records for a period of time, then you can leave them in place with the businesses until you have enough for a warrant.
Data mining for suspicious patterns on the communications and records of millions of Americans that otherwise aren't related to any targeted persons or haven't accessed any targeted websites should be off limits.
Also, even if we lowered the standard to something less than a warrant for foreign intelligence and terrorism cases, you don't "connect the dots" by collecting all the dots first and then sorting them out later. Target known terrorists, suspected terrorists and connect the dots from there using a network approach starting with the originally targeted and monitored persons or web sites.
The only thing you might miss from the approach of only requesting data relevant to an ongoing investigation with particular named targets is the random lone terrorist that doesn't communicate with known terrorists or access terrorist websites that are being monitored. Or perhaps fit some sort of e-profile for some sort of targeted behavior. But that is the line where creepy and big brother meet the road and we shouldn't be treading in those waters... to mix metaphors.
As it stands now everything that is being discussed publicly is about catching people that interact with known terrorists or terrorist web sites which means you should be monitoring all the communications of known terrorists already based on a warrant for a named person and can spider out your monitoring based on frequency, type and content of communications with additional requests based on information derived from the first warrant. The result should also be of higher quality because investigators will be dealing with less noise.