Updating on the website may be daunting, and I can understand that perspective. Sending an e-mail should not be.
The issue with FB is at it's core it is a social networking site, and the internet's brief history has shown they are fads.
Tools however stand the test of time(the little we have to judge). Google, e-mail, Wikipedia. These things swim. How many people have had the same e-mail for at least 5 years, 10 years or longer?
I'm hunky dorey if businesses want to use the latest social networking to advertise and grow their customer base. When business only share vital information their customers need to know, sales, shipping and handling policy changes, only
through social networking and not e-mail that's when I start thinking... "I need a more professional vendor"