Question: I'm implementing a chat system.

What kind of database I should use for logging chat messages?

I need to do some queries to it. For example "give me all the links from user x between these dates"

I've [heard](http://blog.mongodb.org/post/172254834/mongodb-is-fantastic-for-logging) some good things about MongoDB for this kind of stuff. How about other NoSQL solutions? Redis? Cassandra?

How about old SQL solutions? Although I'm very interested having experiences with NoSQL-databases, but I'm not going to it just sake of it :)

I need to be able to handle hundreds of active users.

Answer: 
I've used [SQLite](http://sqlite.org) for this type of logging in the past and it's worked a treat.
My vote goes out to redis(+node). I can handle that scale easily.