A couple of days back, Google released a report showing how many government requests for user data it received in the second half of 2012. Such a report will obviously have some users nervous, but Google's giving us less of a reason to worry today, as it says that it won't give access to Gmail accounts unless the government has a search warrant. We wouldn't expect anything less, of course, but it's good to hear Google say it nonetheless.
If Google did received a search warrant, however, there naturally isn't much it would be able to do. Google has received search warrants demanding that it give up data in the past, as it said in its report for 2012 that 22% of those government requests were accompanied by an ECPA search warrant. Still, this just shows that Google isn't willing to part with data on its users just because the government wants it to give that information up.
Speaking to Tom's Hardware, Google spokesperson Chris Gaither said that the company requires an ECPA search warrant before granting access to Gmail accounts. "If they come for registration information, that's one thing, but if they ask for content of e-mail, that's another thing," Gaither said. So, unless the government has probable cause to suspect you of illegal activity, it won't be able to see the content of the emails you receive and send out.
Between July and December of 2012, Google received 21,389 requests for data on 33,634 users. The company provided data for around 75% of those requests, with nearly 70% of the requests involving subpoenas. Google actually granted fewer requests last year than it has in the past, so things are looking up for user privacy as far as Google is concerned.