There is no exception really. I forbid external hosting of my projects. I do not and have never allowed aggregator sites (Manga-Dex, Manga Rock, Mangafox, Mangahere, Mangago, Mangataders, and so on) to upload my works.
Why you ask?
Scanlation by itself is illegal. And my firm brief in scanlation is that the works must remain free. No one should be making any kind of profit even if it’s few bucks. I do scanlation on my own will and therefore am willing to pay for the server and am willing to spend my own time.
Most of online manga readers (AKA aggregator sites) exist solely to make profit out of scanlations. And I must condemn such actions.