Anyone have a good introduction to NoSQL style databases? When it's appropriate to use them, (dis)advantages of using them, how to query? Ideally a tutorial of how to build a simple app?
* an intro: http://aimee.mychores.co.uk/2008/09/07/post/320
* a use case: http://kore-nordmann.de/blog/couchdb_a_use_case.html
* CouchDB Implementation: http://horicky.blogspot.com/2008/10/couchdb-implementation.h...
* joins in couchdb: http://www.cmlenz.net/archives/2007/10/couchdb-joins
* peepcode: http://peepcode.com/products/couchdb-with-rails
* the 10 minute code-level getting started guide: http://wiki.neo4j.org/content/Getting_Started_Guide
* a full-blown reference example, including diagrams, graph layout screen shots, code walk through etc: http://wiki.neo4j.org/content/IMDB_Example
* the domain modeling gallery, which shows how to model a bunch of domains in a graph db: http://wiki.neo4j.org/content/Domain_Modeling_Gallery
* popular blog post about how to model a social network in Neo4j: http://blog.neo4j.org/2009/09/social-networks-in-database-us...
* how to work Neo4j in python, ruby, clojure, scala & grails: http://wiki.neo4j.org/content/Main_Page#Language_bindings
If you have more questions, feel free go all mailing list on us: https://lists.neo4j.org.
Hope that helps!
Simple twitter clone with Redis: http://code.google.com/p/redis/wiki/TwitterAlikeExample
Their use depends pretty much entirely on what you'd like to do. Network-Structures are naturally best suited for graphbased databases. For Scaling Issues and really fast access redis seems good (haven't used it) and if you are working on really, really large datasets Hbase combined with hadoop might be worth a look.
Here is a small overview presentation: http://www.slideshare.net/chrisbaglieri/non-relational-datab...
Do you have a preference on what language an example app or tutorial is in?
No preference RE: language. Python or PHP would be nice but I can read Ruby as well.