They courted us.
And I know the definition of conflict of interest. I just don't think it is one. Newspapers have run ads for things they've covered for more than a hundred years. Go to nytimes.com. Right now, there's an ad for smart cars on the front page. Search the site for "smart cars" and find a ton of articles about it. CNN and MSNBC and Fox News are all "brought to you in part by" companies they have to cover eventually. A conflict of interest would be, say, being owned by a company we have to write about. But on the web especially, for sites that run ads, they'll be running ads about things they cover, because web advertising is hyper-targeted.
At least, that's the way I look at it. If you want a standard that eliminates all endemic advertising or sponsorship, then I think you're going to be consistently disappointed.
"Other guys do it too!" is approximately the worst argument ever.