I recently had to enhance SimpleLogger by back-porting some functionalities of commons-logging's SimpleLog into it.

Namely, I have added the following:

• optional configuration file; if none found, you get the exact same set of features as the currently released SimpleLogger.
• enable to log more than the info log level
• enable to set different log levels for different Loggers
• enable to show/hide thread name
• very primitive log messages customisation (about the same as commons-logging)

Once again, the new code is totally compatible in behaviour and output with the currently released SimpleLogger.
I also made it so that current users of commons-logging can upgrade to SLF4J very easily.
Finally, I made sure to keep SimpleLogger as simple as possible: we already have fully-fledged logging frameworks, let's not re-invent one!

I think this new implementation would enhance the value of SLF4J, while keeping a perfect retro-compatibility with previous versions.