Very easy and if you are a (happy) user of gmail your life will get better from the first minute you are logged in. If you have other email service it’s also cool. I’m using both yahoo and gmail on it and it’s working great with both of them.
The ability to run gmail in offline mode is also a doable on a Chromebook. It’s very useful, specially, to people the travel a lot and can’t count that their favorite airline will have wi-fi. I’m writing this post from a Chromebook… but since wordpress don’t have a good webapp with some offline capabilities – I’m using ‘Write Space’. Write Space is a customizable full-screen text-editor that lives in your web-browser. It is designed to minimize the distractions that come between you and your writing and the offline capabilities are really working.
If you are a new to Chromebook – check this one and a half minute demo: