Inside Philanthropy magazine has a fascinating list of the top philanthropists in the tech industry (you'll be surprised at who is at the top: Leonard Bosack and Sandy Lerner, the original founders of Cisco Systems).

It also includes the six "least generous" (a generous way to say, "the couldn't care less ") tech billionaires.

Jeff Bezos should learn from his parents:

A libertarian known for his belief in self-reliance--engaged in virtually no philanthropy for years... For a long time, his parents did more giving with their Amazon shares than Bezos did with his billions. Now things are starting to change, with a few high profile gifts going out the door for brain science and cancer research...

Larry Page has short arms:

If this Google co-founder, who's worth $32 billion, has a secret philanthropic life, we'd love to know about it. Because right now it looks like he's a big cheerleader for Google's philanthropic and social endeavors, while kicking the can down the road in terms of engaging in his own serious philanthropy.

Steve Ballmer lost his check book:

We've predicted that he and his wife Connie, a nonprofit veteran, will soon turn on the giving spigot in a big way, drawing on a $19 billion fortune. Otherwise, Ballmer has largely been a no-show in terms of his own philanthropy beyond the occasional big gift here and there.

Larry Ellison has given about half-a-billion dollars to medical research over his lifetime but not much in recent years.

Jerry Yang, co-founder of Yahoo! has made just one gift, $75m to his alma mater -- a comparative drop from his blue ocean.

Bebo co-founders Michael Birch and wife Xochti made out very well when they sold to AOL. Their $595m has partly been spent on $1m to a water charity and much more went here: 

$29 million for a mansion in Pacific Heights and then $13.6 million for a vineyard estate in Sonoma. More recently, Birch has spent millions on his latest cause, which is a private club where the Bay Area elite can hobnob.

Read: Meet the 12 Most Generous Tech Leaders. . . And 6 of the Least