Zuckerberg’s salary cut is being compared to similar moves by other tech titans. Google’s Eric Schmidt and Larry Page are paid just $1 annual salaries. Steve Jobs took just $1 in salary from 1997 until his death last year. Other members of the one-percent/one-dollar club include Oracle’s Larry Ellison and Hewlett-Packard’s Meg Whitman.

Zuckerberg was paid a base salary of $500,000 in 2011 and is set to be paid a base of $600,000 this year. He got a cash bonus of $250,000 for the first half of 2011 and will likely receive a similar bonus for the second half.

Interestingly, he was alone among the top executives at Facebook who got no stock awards for 2011. The board—which is controlled by Zuckerberg himself—decided that he had enough stock to align his interests with the other shareholders. With 28.2 percent of the company, you would hope so.

Zuckerberg’s pay cut could reduce his income tax burden to nothing.

It’s possible that he might even be eligible for certain types of government aid for those with low-income—although it’s unlikely that he would collect them.

In order to reduce his tax burden to zero, Zuckerberg would have to forego any future cash bonuses or additional stock awards. He would also have to stop employing certain Facebook services for personal use. Last year, for example, he had imputed income from the use of aircraft for personal use of about $692,679. He also received $90,850 in estate and financial planning from Facebook.

Can Zuckerberg really live without income?

He almost certainly can. There’s no evidence that he has an exceptionally expensive lifestyle. His biggest annual expense is probably all that flying around. The income he has already received and been paid will go a long way.

Of course, his past income will not really be enough to see him through all of his expenses for his entire life. For those he will need a line of credit, preferably one with a tax advantage, and income that can be earned tax free.

People sometimes talk about the rich “living off the interest” of their wealth. But that’s not really a tax efficient way to live if you are really, really wealthy. It’s better to live off of debt and muni bonds.

The best thing for Zuckerberg would be a home equity line of credit—perhaps multiple home equity lines. He would borrow against the value of real estate he owns. The money he receives from the HELOC is debt rather than income, which means it isn’t taxed. Even better, the interest he pays on the HELOC can be used to offset other income he may earn.