Keeping a log for 20 years for each and every person is practically impossible at the moment, regardless of how advanced you think to seem technology is. Storage is not free and i think its stupid to keep tracking everything without a reason. If you keep logging on everything in the hopes that you may find a connection or something of that sort in the future, you'll need a lot more people to go through that sort of stuff to begin with.
Don't underestimate how deep the pockets are of government defense funds. The NSA has a gigantic datacenter in Utah that's estimated to be storing data on the exabyte order of magnitude (thousands of petabytes). http://en.wikipedia.org/wiki/Utah_Data_Center
edit: Even if they only have 1 exabyte of storage, that's enough to keep 3.3 gigabytes of data for every single person in America (~300 million). I would wager that's more than enough to store the text from everyone's email for many years.
In fact, 3.3GB is also enough to store about 4 hours worth of speech recordings per day for a year for every single person using the best available compression. Double that since you don't need both sides of the call, and consider that the average amount of time spent on the phone is substantially less than 8h, and they can already store full voice for all US calls for many years in an exabyte.
Given that the 1 exabyte is a low order estimate given the size of the Utah data centre, you have to wonder just exactly what they are actually storing or planning to store there. If someone had access to it (and I'm not saying I think the NSA do), the site is physically big enough that you could fit sufficient storage to keep years worth of voice recordings of the total global phone call volume.
The Utah Data Center has at least 100,000 square-feet of data center space. If just half of that space was used for storage then it would be over 27 exabytes worth of storage assuming a density similar to what IBM offers.
You're wrong, storage is cheap and reliable; every electronic communication and signal you generated was recorded and indexed on your true name, even the stuff you thought was anonymous.
Right now, that recorder is temporarily paused for the most part.
An 8TB hard drive costs about $300. I wouldn't be surprised if the log of all the phone calls (metadata) of the US over a year would fit on one or two of these drives.
