Thats 2 different things and in the end its different business - its not "or".
They use the same medium, internet and websites, but thats all.
It should be "and" - you should always aim to have as many legs & feets as possible to stand in your business.
Thats perhaps the golden rule #1.
And i don't mean, as some says, forget all except adsense - thats bull too.
You do not know what happens in the future, perhaps adsense is tomorrow dead. Well, it will be not tomorrow with a high chance, but it WILL be dead at some point in the future, nothing in our business will work forvever.
It sounds like you are telling people to put adsense on their eCommerce website... It's difficult enough to get visitors to your website, and they are obviously looking for something if they land on your site. Mission Accomplished. But you're proposing… let me get this right... To put ads, which obviously your competitors are the ones that are going to be served up, on your website? If, that's what you are purposing, I'd rather just leave off with... Good luck bro.
Anyways... If you've got a website, look at what BlueHatSEO does, he funnels his websites upward, essentially also driving visitors to the money site. Once on the money site, You have to have an end goal. There are 4 types of websites on the internet:
1. eCommerce - Selling products/service. Once a customer lands on this type of site, the only thing you should be concerned with is 1. Converting them into a sale or 2. Having them sign up for your list, so you can eventually convert them into a sale. Sending them to your social media profiles, or go forbid a competitor is not a good idea.
2. Lead Generation - Generating leads for a business. Once a visitors lands on this type of site, there are two things you should be concerned with. 1. Getting them to fill out a form (by showing trust and that you are the authority). 2. Having them sign up for your list, so you can get them to fill out a form later on. In this scenario, you want to give them great bits and pieces of information in your follow up communication, without giving away the farm. The way the OP faggot, bated us into thinking we are going to learn his super elite Haxor level Youtube tips, then baited us into PMing him, that feeling - not a general good idea here, but from a lead generation stand point, perfect).
3. Informative Sites - These sites generally talk about a niche, industry, association, etc. They give information based on a targeted audience, and this is the primary resident of display advertisement. Most of your MFA sites follow this guideline. They are suppose to educate and give great advice, videos, great photos, and great content. Then in the mix of things, you have your advertisements, CPA offers, or direct deals. Done correctly, you can become a monster, and this type of website produces natural organic inbound links, which is what Big G wants to see. Freshness factor is huge here. Collecting a list is essential here as well. Since you can send updates with new topics and get return visitors that trust your name and brand. Then you can sell them whatever you want - if it fits in your niche.
4. Branding - This is a website like Coca-Cola, Pepsi, P&G, that is purely focused on the brand and what's going on with a brand. What this means, there will never be any ads on this type of site, there maybe links to Informative Site about the general niche, and it may even have informative topics on the site itself. It's generally the face of the company/brand online. No eCommerce is done on this type of site. But there are hybrids that will sell their products directly to their customers, which is an excellent idea. Collecting a list is huge here. Since you are going to be communicating directly with your customers or future customers.
I've been doing this for years, there are no other type of websites out there. Social Media sites like Facebook, Twitter, Myspace, all fall under "Informative Sites". WebMD would fall under informative as well. Coca-Cola, Pepsi, P&G fall under branding. Amazon, Pizza Hut, Dominos, etc falls under eCommerce. These specialized portals that generate business for small to medium-sized business fall under Lead Generation (Lawyer websites, Doctor websites, etc).
This why it's important to understand the end goal of website from the beginning before you create it. Once you understand this, you'll be on your way to succeed online. If you're foolish enough to place ads on your eCommerce or lead generation type of website… brother… Good luck. Also, notice, that I give examples of exactly why each type of website should be collecting emails and growing their list. Return visitors, everyone wants them, they are the life blood if the Big G, tells you to go fuck yourself.
So with all that in mind… what the fuck are you talking about not "OR", instead it it should be "And"? Or are you promoting being a jack of all trades, and having multiple websites setup doing multiple things?
With that, I leave off, "Companies fail not because of starvation, but of indigestion." Going in 12 directions gets your nowhere fast. Focus and become great at one thing and scale it.
Carry on.