There's no doubt in our minds that How I Met Your Mother will be on TV next fall. But CBS seems to be at least creating the illusion of doubt by ordering four additional scripts rather than announcing plans to renew the show.
Bill says, "[after seeing the rumors about Without a Trace and Cold Case] CBS may just have decided to play public hardball across the board this year as part of a cost cutting process," which in those cases with somewhat marginal ratings both Bill and I think it makes sense.
But How I Met Your Mother? Is there really any leverage? I'm not sure if this comment on the TV week link is from Bill Gorman (I didn't check with him), but I agree with what Bill had to say (since the show is produced by 20th Century Fox):
Bill: It matters little if CBS actually picks up the show or not, as the fine print of the major syndication deal signed earlier this year requires Fox to deliver 110 half-hour episodes in 2010.
At the end of this year only 90 episodes will be in the can, meaning that no matter whether CBS picks it up or not, Fox will have to make at least 20 more first-run episodes, guaranteeing a fifth season.
Thus if CBS didn't give it a pick up it would likely move to Fox.