When we think of profitable business models, sometimes unconsciously, we tend to think of those large turnover necessarily international with a great structure and personnel involved and provide great value to customers. I'm not saying not met sometimes but it does not mean the force that the business in question is profitable, an easy example would be most airlines are in active. Fulfill all these requirements and many are unprofitable.
 

For a profitable online business must meet the following premises:

• To be considered of great value to users / customers. 
• Replicable business model (easily usable by many users). 
• Highly scalable business model (the increase in sales or income or imply the same increase in costs or structure).
  

THE MODELS MORE PROFITABLE BUSINESS IN INTERNET

Following the 3 characteristics already defined online business will find the following:

• The Affiliates industry:

can already call because growth industry that will experience in the coming years will be important (the same as in the US and UK markets). This business is based on something as simple as generating leads and sales of products and services from other portals. The main feature is that this activity is remunerated objectives (CPA: cost per acquisition). The main actors in this business are advertisers or companies that claim to sell, affiliates (websites offering these products) and affiliate networks (agencies that bring together a number of affiliates to relieve work advertisers).

• Sale online courses and ebooks:

I know it's not the most original business model but if you have to abide by their profitability .... This type of sale is highly replicable, once developed the product can be used by thousands of customers and even enter affiliate circuits.
Related: Turn your blog post into an ebook and sale it

• Sale sass specialized software or services (software as a service):

these models stand out for their high scalability. How costly is the need to find technologically produce the product and get the trust of the first customers. Once located at this point profitability is unquestionable. An example might be a specialized accounting software or a service cloud computing enterprise data protection.

• Drop-shipping:

business model focused on selling products online where this site or produce or store the product. These eCommerce what they do is find a reliable supplier, put their margin and pass them only sales made to the customers it serves. No production costs or storage. It sounds really profitable? If you consider it interesting you can read the following article: "How to find a profitable product for sale online"

• Advertising Business:

This is a very broad category, as well as any online activity that produces many visits to a web page or downloads as to allow the insertion of advertising. I put some examples:

1. Any blog that succeed have the option of monetizing introducing advertising (Importance of advertising)
2. Game or mobile application with many downloads offered for free. Free + advertising model 
3. Web publishing job for free. It sure will have many visits ...

• Business collaborative consumption (P2P):

to understand this type of activity I recommend you read the 5 ways to take advantage of collaborative consumption. This type of business they do is satisfy needs or buying and selling exchange between users. It is very profitable to undertake since only need to produce efficient platforms that meet these needs.

Also read: 25 Profitable business to start now
20 business ideas to make money without invest or a little investment

Given this, you do not have because to think of large structures or large investments to access good returns.

Finally, I want to know your opinion or any saying about profitable internet business models, so we will be updated in comment discussion section.