Reputation management also involves correcting widely-held beliefs about a company/organisation which are flat-out wrong. This happens more than you'd imagine, and work like urban legends - statements of dubious factual content passed around as gospel truth.
Then that's what you spend your marketing budget on. It does NOT mean you should hire an army of minimum wage sockpuppets to post phony reviews or pay media strategies companies to edit your Wiki page.
If you can't repair your image honestly, you're either not trying or you don't deserve the image you want. Social media did NOT change the rules. In fact, it may have made them more important than ever.
How often have you seen a Slashdot post condemn a company for something it hasn't done, only for that post to be modded +5 and accepted as an honest appraisal of said company?
In middle school, there was a guy who called me a bad name in front of a bunch of people. Everybody laughed, and it was the equivalent of a +5 mod. Through my behavior and speech, people soon realized it wasn't true. I did not hire 20 strangers to give testimony or to scream in the guy's face.
The last thing you want to do when a damaging falsehood about your company is spreading like wildfire across the internet is to sit there and do nothing, as that only guarantees it will continue unabated.
To paraphrase a famous politician, business ain't twiddlywinks. Bad PR is not an excuse for corporate dishonesty. I'm sorry, it's just not.