I guess it is obvious but gas has just become a weapon in the fight against terrorism. This was a shining example of what can go wrong. Unfortunately, I suspect we will seem a lot more use of gas in terrorism confrontations before we see less!
I guess I should comment on why I think Exchange is the way for a small business to go. Although a person like me might enjoy playing with IMAP from different vendors and comparing it to Exchange and Notes, most small businesses want to focus on their business. Email is an important tool in supporting the business but is also a source of major headaches such as spam and viruses. With a product like SBS2K you can almost ignore the upfront cost and focus on the headache issues. At this moment in time the tools to minimize those headache issues appear to be more robust for Exchange than the other products. It just doesn't take too many lost hours to justify a more professional approach to email.