Can an online business fail?

This is something I have been thinking about since I have seen recently some people going from just a few dollars a month in revenue from their websites to over a couple of thousands dollars a month in just a few months time.

One of the biggest reasons for failure of course is people not working hard and finally just giving up.  But if someone works really hard on their online business can it still fail?

There have been plenty of web start ups that have started with an idea, got some investment and then gone bankrupt.  There is also quite a bit of risk running an ecommerce store that sells physical products.  What if a company buys stock that never sells or customers aren't happy with the product and demand a refund?  Certainly an ecommerce website has its risks, so how about a website that just displays content?

If you made a content rich website in a niche that doesn't have any advertisers or products to sell, it could be very difficult to make money.  As long as you didn't outsource the production of the content, you will just be left with a website that produces little income, perhaps not a complete failure.

Treating your website as a business by actually doing research into the niche, including the potential target market and monetizing options for the site, will decrease the likelihood of failure.  If you produce a useful website with valuable content and spend an equal amount of time marketing your website, I really doubt that you can fail with an online business.

What do you think?  Can an online business fail?