Advertisements: internal and external
If you want to get rich by placing ads on your site for other sites or services then you better be sure your site is going to get a lot of traffic or at least don't go spending all those pennies until you've seen them coming in for a few months. The most popular sites that will pay you to advertise for them aren't going to do anything for you unless you are getting plenty of relevant traffic to your own site.
Some of these ad sites require you to use code that can interfere with the coding for your own site, so it's important to consider the choices they are offering you as well as where you really want those ads to show up. It's also just as important to understand the nature of those ads and how they work. If your site is brand new then you aren't going to want someone else's ads getting in the way of your own content, save that for when your site is already getting over a thousand hits a day.
You also aren't going to want just any random ad showing up on your site, so it's important to consider your own content as well as the ad service you are thinking about selling your site's space to. If your site is about an abortion clinic that you own, then you need to understand that the content of your site will likely include things that could easily get you advertisements from anti-abortion sites through the most popular ad services. This is the sort of situation where humans have created something to serve them but laziness has created something that can, sometimes very harshly, backfire on us.
The same is true with what other places you may choose to advertise your own site. A 'good' site isn't going to want to have it's link displayed on a 'bad' site. The purpose of your site may be generic enough that it can appear anywhere, but reaching your target audience should always be a primary goal. You aren't going to do much to help your site by simply flooding the internet with your ads at random. Analyzing and specifically targeting a handful of appropriate sites and communities will do more than spamming your link to a boatload of random places just because they're free.
We are humans, surprisingly less expensive than 'bots'. Our attention and discernment will put your ads in more useful places. Our artists will make those ads stand out by being attractive, unique, and relevant. Give people what they want and they usually take it.
