I have yet to see another online service for viewing spreadsheets that works as seamlessly as the Socrata sets. It seems no matter how much data or how many rows there are - it is always consistently fast.

I'm curious to find out or learn some details as to why it works so well, or who/what is powering the sheets, and if possible, what kind of code/language or application allows it to work so much better than sites that host spreadsheet services.