In Feb 2007 WP.com (WordPress) blogged they where running:

• 152 Physical Processors
• 511 GB of RAM
• 174 Hard Drives
• Several Tera-bytes of Storage

Now 4 years later they are at:

• 2,475 Physical Processors w/ 8,291 CPU Cores
• 8,200 GB of RAM
• 1.3 TB RAM Drives
• 1.3 Peta-bytes of Storage
• 8.9 TB of Solid State Disks
• Plus Amazon S3 as a Backup

So here’s my two cents to add to the load: That’s pretty impressive numbers for a blogging service.