On the NY Daily News site: Keith Olbermann’s vacation isn’t going so well.

He was forced to apologize yesterday after more of his E-mails found their way to my inbox and exposed the host of MSNBC’s “Countdown With Keith Olbermann” as insulting and frequently obscene in an acrimonious exchange with two viewers who taunted him.

Olbermann’s antagonists, who asked not to be named, repeatedly claimed in their June 8 E-mails that dead Al Qaeda terrorist Abu Musab al-Zarqawi was Olbermann’s “hero,” prompting the television star to advise: “Hey, save the oxygen for somebody whose brain can use it. Kill yourself.”

After I forwarded that and other E-mails to an MSNBC exec, Olbermann wrote: “I apologize to anyone who might take offense at my part of this correspondence. It goes without saying that I should not have replied to these abusive and hateful E-mails, but I wonder how many of us could receive literally hundreds of them questioning our patriotism, religion and ethnic origin, without succumbing to the natural wish to confront such hate?”

Here are some examples of Olbermann “confronting hate”:

# “Given how far you are from knowing your a- from your elbow about my industry, you couldn’t be stupider, wronger, or dumber …”

# “Go – your mother.”

# “You ‘Americans’ still watching that evil f- O’Reilly?”

Apparently, they are. Fox News’ Bill O’Reilly draws six times the viewership of his 8 p.m. weekday rival.

MSNBC declined to comment yesterday, but Olbermann is scheduled to return to work on Monday.