One of the reasons that small businesses go online is that a well designed website for even a one man business can have just the same presence on the web as a multi-national corporation.
Communication, marketing and printing costs are lower too, as is the cost of using full colour.
Larger businesses see it as a way to reinforce not only their brand (which is becoming increasingly important), but also as a way to reinforce an image of leadership and potential.
All businesses see it as the key to keeping ahead of the competition.
There are other reasons, too numerous to go into here. Don't think the web is not for you, it is the future.
It will change society, it will change our entertainment, and the way we do business.
It will also reshape our town centres as financial organisations, brokers, agencies and other businesses first merge, then abandon their overhead-laden town centre shops, and opt for access to a bigger market with lower overheads direct and live on-line.
As someone said of the web, "There's no point in ignoring it, it's as inevitable as the telephone".