Ever-easier public display of your reputation

Clay Shirky wrote:

As the net gets bigger and karma, previously bottled up in human relations, becomes convertible for real currency, in everything from ZeroDegrees/SMS.ac style spam to real sales of virtual characters to this, we are going to have to find ways to defend against this sort of karmic hijacking.

In another example, and following up on my post about reputation-checking for dating,
Opinity nows offers a cross-platform reputation management service. Susan Kuchinskas reports the story here. Opinity aggregates your online reputation across all the sites that allow you to develop a reputation.

My greatest difficulty with this is that some people are perhaps bad girlfriends but good ebay vendors. So I only care about that woman’s reputation on ebay (not on jdate)… but then what do I need Opinity for? I can just use ebay’s rating system.

I’m fascinated to see how people abuse Opinity’s system, which they will. How do you think people will try to game it?