A statement of the obvious? Not necessarily.
When I first started researching the idea of working online I found a gazillion sites offering me 'foolproof' systems that would 'guarantee' to have me earning thousands a week by this time next month.
And none of them involved a product.
Many (if not most) of the MLM or Direct Sales type businesses I've seen, some of which do have good products behind them, focus on signing up new members.
Not on the products.
Adsense is a popular way for people to monetize their sites but, again, no product. Plus, if you're going to make money from Adsense you usually need to do a LOT of work for a paltry return.
And, as soon as Google changes it criteria, your income can be cut off. Overnight.
So what's my point?
To have a sustainable, profitable online business you must build it around selling a real product or service.
The primary off-line businesses I can think of that built an income based on complicated, non-product related deals are the banks.
And look what happened to them in 2008.
Successful, sustainable off-line businesses sell good products that add value to people's lives. And it's no different online.
It doesn't matter whether your product is an information product, software, a membership site or a service. As long as it adds value and meets a market need, you'll have the basis for a good business.
How to get a product to sell?
Actually, getting hold of a product to base your business on is not that difficult.
Here are 4 ways:
Create your own.
If you're a programmer or have specialist knowledge in anything, you can create a software application or an information product (an ebook describing how to do something) and distribute it online.
Sell someone else's product.
Affiliate marketing is well established and a lot of people make a lot of money from it.
With affiliate marketing you'll earn a commission from the product owner for each sale referred by you.
Buy the re-sale rights to someone else's product.
In this model you get to keep all the revenue from each sale. The downside is that where people are selling re-sale rights the products, as they stand, are often not good enough for you to make a living off.
You need to edit and add your own value to them and, before you do that, you need to make sure the re-sale rights enable you to do so.
Set up and run a membership site focused on your skill area or simply sell yourself as a consultant
So pick an area you're interested or expert in, and research your market. See what kind of questions people are asking and what kind of problems they have.
If you know how to fix their problems develop your own product to do so.
Otherwise, find a product that fixes their problems, via one of the other methods above, and build a business around it.
For lots more details on how to find a business, establish whether there's a real demand for it and find a product to sell take a look at this free eBook I created - it contains 65 pages packed with how to's on setting up your own online business.