Ads are for the ones who doesn't have an account.
And who knows ? Maybe the admins are millionaires that opened this site as a hobby. So they don't need money ? :3
Oh and I think (not sure) that the more there are people on this site (google search), views etc they get some money of some sort. Don't know.
If you read manga here as anon, the page link will link to an article while as a user with an account, you can see the manga name, chapter and page in the link. while an anon reading the manga page by page, they actually read the article too. So most probably that is where mangago afford itself. I believed there's a lot of user here as anon rather than a user with account so that is why mangago does not have to open for donation (just my own theory ╮( ̄▽ ̄)╭). Before this, there's an ads on every page (read as anon) and after the last page by clicking next will direct us to the article page but now there's none but the article link is still there.
How does mangago fucntion? I mean it has no ads, no donation pool, how does it afford itself, im just curious hmm....