If you have a bad online reputation caused by some big audience blogger dissing you, then use four recruitment consultants when looking for a new role rather than the usual three, as approx. 27% will reject you.
Since the cost of adding another executive search agency to your job hunting schedule is normally a few emails and maybe a telephone call (despite claims to the contrary, in my experience they rarely interview candidates and instead leave this to the client) then the additional cost is probably around £10-£20 (including your time at minimum wage).
However, the time and effort involved in generating a good online reputation is vast and so is the cost of losing it by becoming known as a blogger who likes to take pot shots at people, especially if those people can't or won't fight back.
Once you start hurling abuse online at someone who is unable to mount a fair defense, then this is just plain bullying. Any moral high ground is lost and any valid point is now insignificant.
In terms of the human impact, the blogosphere is more of a blogopond and we do tend to exaggerate how big the fish are.