It's complete and utter garbage. It's not a matter of 'I've got nothing to hide, so why should it matter.'
Look at it like this. Can I see you bank and credit card statements for the last 15 years? Do you have blinds or curtains on the windows of your home? How about I take nude pics of you and then I own all the rights. I can then share those with anyone I want... like your neighbors, co-workers, family? But you didn't do anything wrong so you've got nothing to hide, right?
It's not just cell numbers and e-mails. It doesn't look once, then delete's everything. They save everything. They will know every phone call you made, every internet search, and every e-mail you've sent, from now until you die.
But wait.. they are only tracking extremist groups and terrorists right?
If you are a Christian, you've recently been labeled an extremist. If you belong to a Patriot Group, or local militia, you are an extremist. Tea Party...Extremist! The definition they set is expanding to cover more and more people. So if you are not on the list, you soon will be.
Imagine you, or someone you know is doing research for a book, article, homework.. and searches for Terrorist Groups, Terrorist practices, attacks, IEDs, ect. You've just been potentially flagged. Now they not only go through all of your stuff in even more detail, but everyone you know. You might even get a visit from guys driving black SUVs.
This can also be tied to the IRS questions. They were asking certain political groups for WHO members are and WHO donated to them. Do you think they will let that just go away once collected?
Nope.. If let them get away with this, they will keep doing pushing the boundaries of our rights..