You can be a honest and tax-paying citizen of society and still get audited. There's always the chance that there may be a mistake somewhere. The US tax code is not simple. Even if you shell out $20-$80 a year to do it via TurboTax, H&R Block, whatever, there's always room for a mistake.
And even if there are no mistakes, simply being told you are being audited would make most people's heart skip a beat.
The article didn't quite cover what approach the IRS is using.. Whether they are taking already flagged people and getting more info via social network profiles, or if they are using social network profiles and using that as a deciding factor on if one should be audited or not.
The former I don't have much of an opinion on. The latter I don't like the sound of one bit.