At one time, Cobalt servers were the most popular Linux-powered servers for ISPs and Web hosting companies. Despite this, Sun started backing away from this platform over the last couple of years. And, now Sun is retiring the last of the line, the RaQ 550 server, in mid-February 2004. The company, will however, continue to support Cobalt servers for three more years.
As for the future, Sun will be introducing Linux and Solaris on Intel AMD-powered Sun Fire servers early next year.
For more on this story, see NetCrafts article.