Wouldn't be great to change pet from time to time for those wanting to do it? I mean, you could have a little dog for a while and then change it for a cat, an then for another dog breed, a rabbit, and so on...
This web would connect people wanting to exchange their own pets with others with no cost.
I should have added that it is not an idea for people very attached to their pets but those who get easily bored, because, although you'd rather think they do not exist, they do, and a web like this would at least satisfy their desire of changing constanly and wouldn't end abandoned at the streets, in the forests and so on...
I definitely didn't explain myself correctly and I accept my idea has been misunderstood