HP did not return requests for comment. Ari Fishkind, an IBM spokesman, says such accusations are "richly ironic, since open source was deemed socialist, or worse, in some circles."

"Will making open source contributions of value sometimes make other vendors work harder to improve their commercial products, or encourage them to contribute innovative code, too? Probably," said Fishkind.

But true "predatory behavior is locking customers into a particular platform, or acquiring companies then discontinuing support for a product in favor of an expensive alternative, or menacing customers with patent lawsuits."

Some say that the sequence of events that critics such as Haff portray is hardly cut-and-dried.

"Just because a big company open-sources a product doesn't mean it will get used," says Neelan Choksi, vice-president for Interface21 Ltd., which makes the popular open-source Spring framework for Java and J2EE applications. "Open-source is a democracy -- people vote with their feet."