Obscurity Portal's Existential concerns largely revolve around a possible loss of its obscurity status. In an unlikely, but not impossible event of the Portal becoming widely known, it's claim of obscurity would be destroyed.
There are several solutions to this problem.
The probability of the Portal attaining mainstream success is extremely low, while having a small but dedicated following will not upend its obscurity claim. So, there is no use worrying about this.
If it does happen, first of all Obscurity Portal can be called that as a matter of its origins. Second, there will never be a shortage of things obscure. It can still end up here. Additionally, mainstream interest in a resource dedicated to describing obscure things does not necessarily make those things less obscure.
This ^^^
By putting together a collection of creative ideas that nobody knows about, Obscurity Portal essentially provides a sandbox for ideas to be plagiarized, especially because of the way they are presented: as obscure and silly.