"I am 100 percent certain that there are literally dozens of people horsing around with OpenSolaris inside Google," said Stephen Arnold, a technology consultant and author of The Google Legacy. Moving to OpenSolaris, he said, would be a natural move for Google, with its large number of former Sun employees and its never-ending drive to push the performance of its data centers to the hilt. But Arnold said he doubts that Google, which finished rolling out its highly-secret data centers in 2004, is deploying OpenSolaris widely yet. "Will it quickly replace Linux anytime soon? No," he said.

Solaris' recent popularity could reflect something of a rebound for Sun, which rode high during the Internet boom but was hurt by the postcrash emergence of Intel-based servers running Linux. It could also vindicate Sun's embrace of open-source, though its efforts to create developer interest in OpenSolaris remain less successful.

There are just 15,600 registered members of OpenSolaris.org, and 10 percent of those are Sun employees. By contrast, there are 25,000 registered members at one Linux project, OpenSUSE, and 380,000 registered members of OpenOffice.org, which was also open-sourced by Sun back in 2000.

While Linux boasts 665 user groups worldwide, OpenSolaris has just 32. And only five non-Sun distributions of Solaris have emerged, compared with nearly 400 Linux distributions, according to DistroWatch.com.

Stephen Hahn, technical lead for OpenSolaris, argued that other statistics, such as the number of bug reports and code contributions from OpenSolaris community members, are better indicators. And he said a limited number of mutually-compatible Solaris distributions is preferable to the chaotic Linux landscape.