Note on this list the stubborn persistence of Yahoo’s Geocities at No. 6, the rise of Yahoo’s Flickr at No. 7, Six Apart at No. 10, and the presences of Chinese sites like Baidu Space and 56.com. The real surprise, though, is document-sharing site Scribd at No. 16, with nearly 24 million worldwide uniques. 1. Blogger (222 million) 2. Facebook (200 million) 3. MySpace (126 million) 4. Wordpress (114 million) 5. Windows Live Spaces (87 million) 6. Yahoo Geocities (69 million) 7. Flickr (64 million) 8. hi5 (58 million) 9. Orkut (46 million) 10. Six Apart (46 million) 11. Baidu Space (40 million) 12. Friendster (31 million) 13. 56.com (29 million) 14. Webs.com (24 million) 15. Bebo (24 million) 16. Scribd (23 million)
James Hamilton has published a thorough summary of Facebook's Cassandra, another scalable key-value store for your perusal. It's open source and is described as a "BigTable data model running on a Dynamo-like infrastructure." Cassandra is used in Facebook as an email search system containing 25TB and over 100m mailboxes. # Google Code for Cassandra - A Structured Storage System on a P2P Network # SIGMOD 2008 Presentation. # Video Presentation at Facebook # Facebook Engineering Blog for Cassandra # Anti-RDBMS: A list of distributed key-value stores # Facebook Cassandra Architecture and Design by James Hamilton