Defining Megayachts

Thanks to you all for the warm welcome originally. As I'm getting up and running at PMY, my first task is to work on the Top 100 list & develop a Megayachts column for PMY - a nice way to ease in, eh?

I would love to get the opinions of some passionate megayacht followers as to what you consider megayachts. Is it anything over 100' LOA? Do you think it is necessary to classify the bigger boats as gigayachts?

Or is it more about luxury? Does it need swimming pools and helipads and the like to be defined as a megayacht?