They wrote about MongoDB for logging recently: http://blog.mongodb.org/post/172254834/mongodb-is-fantastic-... - capped collections sound ideal for short lived logs.
It would be interesting to write a command line script for piping Apache logs in to MongoDB, using Apache's "piped logs" feature: http://httpd.apache.org/docs/2.0/logs.html#piped
Not officially supported, but someone is working on a C# driver: http://github.com/samus/mongodb-csharp/tree/master
I'm using it for a new project. I hope it performs well for read-often, write-rarely apps as well.
So far so good over here :)
no brainer for write-often read-rarely types of applications (logging, metrics
I'll probably be re-writing some logging functionality in it, actually. I love asynchronous operations. AKA, "YAY! NEW TOYS!"
Anyone who is looking for an alternate to SQL should check MongoDB out. Now that they have reached a stable milestone it seems like a no brainer for write-often read-rarely types of applications (logging, metrics). It's lightning fast.
Setup is a breeze now that they have distributable packages for Mac/Linux/Windows in both 32 and 64 bit versions available.
I do wish they would create an officially supported C# driver. I think it would really give their adoption rate a boost.