that's not the question here. google scans the text of email so they can deliver relevant ads. they freely admit to that, have never tried to hide it, and have been doing it for 10 years with little to no public concern about it. The only question to be decided here is whether scanning your emails for the purposes of advertising counts as wiretapping.
If Google can win the argument that the way they're using their interception and reading of messages in serving personalized ads is a part of their everyday business activities, it seems to completely undermine the purpose of the law. Google, with G+, is trying to itself be a single unified product with all of these features. Social networking is a feature, videos are a feature, websites, blogs, instant messaging and email and targeted advertising. If Google can say that displaying targeted ads is a part of their normal business activities, then what activity does the law against wiretapping actually protect against?
If Google can read your email for the purpose of enabling a tangential feature of displaying targeted advertising to you, how does that same logic not apply to me if I claim my normal business activities are delivering your mail while opening it, reading it, and selling useful information I find inside of it? I could say it was essential to my business, because I actually deliver for free and just pay my bills with the info I sell.
and regarding your last paragraph, you have to remember that this is all consented to by the user. it's not akin to somebody reading and selling your mail before they deliver it to you, it's akin to somebody doing that because you hired them to.
And I don't follow why you think once you have a reason to use data for one purpose, you automatically have the right to use it for any purpose.
It isn't a good thing for Google to try to make loss of privacy seem like business as usual.
But what about a non-Gmail-using party who sends emails to one or more Gmail users? Is Google building a dossier on them based on their return address? Are they associating that person's email with other tracking mechanisms Google employs?
I don't know if Google does these things, but if they did, would it be OK?
If some or all of the collected raw data is at most a 'probably foreign' request away for military spies, is it OK to scan and store every bit of data that would be permissible in a mutual-trust-based civil society?
You signed up for Gmail knowing how your email service is being paid for.
As for National Security, well, the hell with it! No role for a nation or security unless I get to define the parameters of my privacy!
Snowden 2020! (When he'll be over 35 ;)).