question about reputation

[Wei Dai <weidai@eskimo.com>]

In an economy based on positive reputations, how does one acquire a 
reputation capital?  One way may be to initially perform services at a 
price below cost, but this has some problems.

For example, Alice starts a anonymous consulting service, and announces 
that she will answer the first ten queries for free.  Upon hearing this, 
Mallet immediately starts another consulting service, and announces the 
same offer.  At this point Mallet can simply forward his customers' 
queries to Alice and Alice's answers back to his customers.  Thus, he gains 
reputation at no cost.

On the other hand, this "man-in-the-middle" attack can also work against
conventional True Name based services, but perhaps with less effect.  Has
anyone ever heard of this being done? 

Is there a better way to acquire a good reputation?

Wei Dai