Anyone that knows me knows that I am a VERY hard working person. However, I have never liked to work on the weekends and on the occasions that I have to, I have always let people know that this is a problem. However, reading through Google's and Yahoo!'s blog just makes me realize how warped the sense of work / life balance is at those companies. Do people at Google and Yahoo! not care about having a life?
Here is a quote from Google's blog
When we launched Google Talk, some people told us what a great idea it'd be to add chat to Gmail. True that. So a couple of us Google Talk engineers approached the Gmail team. They were excited about the idea, and we got to work immediately -- spending a lot of not-so-lazy Sundays huddled in a conference room.
Here is a quote from Yahoo! blog
In addition, we’ve been working hard to make My Web faster and lay the foundation for future functionality. It took us a little longer than we expected over the weekend, but the good news is that all went well and we’re in good shape for what comes next.
It seems like they are all bragging about working weekends and not having 'lazy Sundays.' What is wrong with a lazy Sunday? Is this where we are headed? If yes, I don't want any part in it. I don't mind working super hard but when companies and their employees are bragging about working weekends it just makes me sick.
Ok, now its time to get back to work! Perhaps I should start to write and brag about my 10, no make that 12 hour days. Just kidding, it is a 16 hour day. Ok, I will stop my rant. Things over here are great and we are having a good life balance, working hard and having lots of fun! 
This is a concept that I'm constantly resolving to achieve but never quite able to execute!
Personally, I think Yahoo and Google aren't bragging about having no weekends as much as they're trying to show how hard they work and what kind of personal sacrifice they'll make to 'get the job done'.
There are plenty of people who would never want a job that requires them to give up their lazy-Sundays. Yet they'll still be amazed at the dedication of those that do. People like you and I find that repugnant, but it would appear that the masses are nearly evenly split on how they view work ethic and what constitutes and taking it too far.
Just to play Devil's Advocate (DeNiro is so awesome), Google also keeps a company image like they're coolest place to work with a portion of time required to be spent on personal projects and such. If even half the hype works out in their office, grueling programming weekends could still seem like little more than intense personal weekend coding.
My, my.
"All work and no play makes Jack a dull boy".
Not to forget the social and health impact of no down time: burn out, thin relationships, disconnect from surroundings and environment, obesity, and and and.
How will we ever be able to keep up this pace during 40 years of working life (assuming retirement will be at 65).
The company (Google included) will toss you out one day anyway, without a thank you, and then where are you?