the exchange blog, You had me at EHLO, has a post about some show case papers for Exchange. one of the coolest parts of the post is as follows:

“The Exchange messaging infrastructure at Microsoft is a large messaging environment that consists of:

- 116 servers running
Exchange Server 2003 (including passive clustered nodes), of which 63
of the 69 mailbox servers are in clustered configurations running
Windows Server 2003.
- Four Exchange sites in regional data centers worldwide.
- Messaging services for approximately 102,000 users.
- More than 118,000 total mailboxes (including system mailboxes).
- 200-megabyte (MB) storage limit for each mailbox.
- More than 10 million messages globally per day. (Approximately 3 million are internal e-mail messages.) 
- 20,096 Smartphone devices that access Exchange.
- 5,145 mobile devices running Windows Mobile version 5.0 that access Exchange.
- 2,279 devices not running Windows Mobile but using an Outlook Mobile Access connection.
- 60,482 users connecting to Exchange by Outlook Web Access 2003.
- Approximately
60,000 users connecting to Exchange by remote procedure call (RPC) over
Hypertext Transfer Protocol (HTTP) and Outlook 2003.”

That is some cool info. 10million emails a day! 102k users! mad stuff!
bk_keywords: microsoft exchange, windows mobile, outlook