I designed my first website over 15 years ago, when the technology was brand spanking new. I was still a teenager. Now this is what I do for a living... that is print and web design, seo, marketing, content development, etc.
There are literally TONS of disadvantages to not marketing your product online. Perhaps the primary disadvantage is that your competitors ARE... and they are gaining national brand recognition and selling to people who will never set foot into their store.
If your target audience is online, it's suicidal to your business and marketing strategies for you not to be there as well.
On the other hand, if you market primarily to octogenarians or people who are never online, you don't miss anything.
Answered May 19, 2011
Edited May 19, 2011