Does it matter how I format the name of a function?

Yes, I know, silly question. But this question has been bugging me for a while, and now I just want to know if it really matters.

Basically, I just want to know if it really matters if I format a function like longWordFunction() instead of LongWordFuction() or longwordfunction() like other people do. That is my question.

Thanks for answering, afroraydude