Back in the days of Resort (or at least, the days when it was highly active), there was a lot of silliness in net.speech that arose. "Ooooer!", "hihihihihihihihi", and "huggles" were among the big memes that a lot of regulars used. I got annoyed with typing out so many hihihihihihihis all the time, so quickly shortened it to just the "hihi". After that, "bibi" and "nini" were easy leaps of silly logic, and I've stuck with the set ever since.
So, there ya go. Completely useless information about me, just what you always wanted!