how FriendFeed implemented schema-less storage
After some deliberation, we decided to implement a "schema-less" storage system on top of MySQL rather than use a completely new storage system. This post attempts to describe the high-level details of the system. We are curious how other large sites have tackled these problems, and we thought some of the design work we have done might be useful to other developers.
this kind of detail is really helpful to those who are hearing about schema-less data modeling, but are not clear on how it can really work. breaking past the 40 year-old relational data-model will take some time. but it's good to see more public examples that are working.