Most have similar rules to Google, such as a limit to the number of the network's ads per page (usually three), and termination for clicking your own ads. In most cases, you can run multiple ad networks on your site without violating terms of service, but you'll want to read the rules of each network before doing it. Further, you want to avoid your site becoming so overwhelmed with ads that your readers can't find the content.
Other Income Options Besides Ad Networks
Ad networks, especially AdSense, are great options because you can join as a new blogger or website owner, and they are easy to use. But they're not the only ways to make money from your website. In fact, as your site traffic grows, other monetization options might be better. Here are some other money-making ideas you can use instead of, or along with, ad networks.
Affiliate Marketing: Like ad networks, affiliate programs are usually free to join and easy to add to your website.
Sell Your Own Product or Service: Creating your own product or service, as opposed to promoting someone else's through affiliate marketing, can earn you significantly more money. This is especially true with information products or online courses that are inexpensive to create and sell. Other options include ebooks and freelance services.
Coaching or Consulting: As an expert in your topic, you're in a good position to help people beyond the information you provide on your website or blog. You can offer more in-depth help through coaching or consulting.
Sponsors: When you have a good amount of traffic and influence over your audience, other companies will pay to sponsor your website. They can sponsor your entire site or a single page or post.
As you can see, there are many ways to earn income from a website or blog. But many require that you have significant traffic before you'll make money. This is where AdSense is a good beginning monetization option. You don't have to create anything, you can join the day you start your blog or website, it's free, and it's easy to add the ad code to your website