So you have a million houses, festivals or gnomes you want to display on VE, but when you display them all at once it is messy and slow. Why not try clustering them?
Basically the issue is when you have large number of pins to put on the VE map two problems occur.
1. If you go and add them all it is going to slow down to a crawl or timeout.
2. If you have pins at a close proximity at certain zoom levels they are going to sit on top of each other and be completely unusable.