This is good news for small businesses. MSE is an excellent product -- I've recommended it for some time now, as it does a terrific job of blocking worms and viruses, along with spam and other unwanted malware. It's as good as most of the consumer-level security offerings from companies like Norton, McAfee, Trend Micro and others -- and there's no yearly fee to pay.
If I had a small business, I would seriously consider cutting my costs and replacing what I have in place now (assuming it's one of the consumer-grade offerings mentioned above) with MSE. You should, too.