Copernic to be Acquired; Who's Paying for Desktop Search?

Amit Agarwal points to a news release that Mamma.com is looking to acquire Copernic Technologies.

I wonder what this will mean for the free Copernic Desktop Search.  I like CDS, but I don't see the unique advantage it delivers in what's getting to be crowded market.  What niche can Copernic carve out when much bigger guns like Microsoft and Google also deliver a free product? 

More importantly, is a free desktop search program viable for the long run?

Niki Scevak of Jupiter Research is quoted saying that free desktop search software lacks a clear revenue model on its own, since revenue is really only tied to "searches of commercial interest." 

Essentially, how is anyone going to make money by letting me search my own hard drive for my own files?

A number of possibilities exist, including: 

1) Show me advertising while I'm searching.  (The quandry here is how do you make advertising effective but not intrusive.)

2) Show me similar information from the Internet, whether I want it or not. (That seems to be Blinkx niche now. Personally, it's interesting but not my ideal. When I want to search the Internet, I will.  When I just need to find something on my own computer, searching the Internet is wasting my time.)

3) Tie this tool into other pay- or advertising-driven products in a way that I want (or need) to use both.  (Google and Microsoft's approach)

4) Skip the whole dance of giving you free software and finding someone else to pay for it -- and just charge you for the program (X1's approach. They just need to cut the price in half.)

My guess is that some of these approaches more shaky than others and that ultimately many of the current players will be bought up or will abandon this market.