: Does it make sense to implement own ad system on a website? I've done research on viability of AdSense to put on our website and found that this is probably a bad approach for the following

Posted in: #Advertising #GoogleAdsense #UserFriendly

I've done research on viability of AdSense to put on our website and found that this is probably a bad approach for the following reasons:

The ads are quite often not relevant at all for users
You can't make enough money even if you are huge(see answer for this question for example)
People are annoyed by this

So I had the following idea in mind - instead of putting AdSense or some other ad tools maybe it makes sense to implement custom ad tool? I'll explain:
The site I am working on is focused on quite niche field, i.e. all users are interested in quite narrow services and products. It might be good to make direct contracts with companies to advertise their products, meaning for each ad we show on a website we talked directly with the company, discussing the ad campaign, making it more personal endeavor. I see some benefits of this like:

We can show ads that we are sure will be of value for users
We can prevent adBlock from blocking it
Since we control everything we can make it as user friendly as possible
Probably will be more profitable

Are there some disadvantages here? Do I miss something? On the first glance this seems more reasonable, at least for niche website, but to be honest I don't see it implemented very often(or I at least not aware of it when I look at ads). Or maybe there are some legal issues?

The only disadvantages I see for now are getting initial companies interested and extra development time.

Edit:
To avoid opinion-based answers I am asking if there are companies that use this approach and shared some data. I couldn't google well since this is not popular method I suppose.