How does Google use Percolator, Dremel and Pregel?

Can you provide some insight into how Google uses Percolator, Dremel and Pregel?
Blind Five Year Old, SF, CA

Read more:
Percolator: http://ift.tt/rQPR9P
Dremel: http://ift.tt/PqVxBq
Pregel: http://ift.tt/Pn6qsd

Have a question? Ask it in our Webmaster Help Forum: http://ift.tt/I2Tkrj

Want your question to be answered on a video like this? Follow us on Twitter and look for an announcement when we take new questions: http://ift.tt/oNYtY3

More videos: http://ift.tt/ruEWTI
Webmaster Central Blog: http://ift.tt/q2Ln8P
Webmaster Central: http://ift.tt/p8sY8n