The difference between selling your own ads and using a network is the middleman. Google takes a cut, so you potentially end up with less.
If the paid time that would be lost while selling ad space outweighs the cut Google takes, it might not make sense.
I suppose there's also the possibility of hiring a firm that deals with that kind of thing, but I don't know anything about that. It's probably not cost-efficient if your startup isn't big enough.
I was sort of curious about that middle ground. LangPop is not 'my startup', it's a side project type of thing that I'd like to make some extra cash from.
If the paid time that would be lost while selling ad space outweighs the cut Google takes, it might not make sense.
I suppose there's also the possibility of hiring a firm that deals with that kind of thing, but I don't know anything about that. It's probably not cost-efficient if your startup isn't big enough.