When talking of a MSN bomb i refer to my blog post about the lousy domain detection and search algorithm of MSN. So I perceive a MSN bomb to be an action – using a loophole in MSN’s “algorithm” – intending to rank no.1 for another domain name.
While ranking for domain names does not seem to be an issue yet, you could probably make a living by fishing for noobs and misguided MSN users mixing up MSN search with their browser bar. You would be surprised how many users type domain names into search applets.
These are the domains which might suffer first from their position being taken over by sneaky MSN optimizers:
1. ebay.com – I heard of frames happen to work well with ebay. What’s the ROI of having all IE-noobs coming to your site, when looking for ebay.com?
2. amazon.com – How many MSN users are able to distinguish between amazon.com and an affiliate site? 
3. wikipedia.org – Newbies like wikipedia very much and tend to look for it quite often.
4. Even worse – Phishing: This loophole could be a target of phishing too. Because: MSN never would deliver a phishing site to you, would it?
5. Yahoo.com – In case they lose their top ranking, they’ll just consume MSN, I guess.
Why is google.com missing? ….. Google Blogoscoped will rank no.1 for www.google.com soon. There’s nothing threatening about it. 
By the way: Is it more likely to have MSN change that algo than having them review those SERPs?