Welcome to Dark Chestnut.
I blog here on Common Lisp topics, mostly about things I encountered while building a production grade web application.
Run Common Lisp web applications in the cloud.
I wrote on this topic before but the landscape has changed a lot since then.
Although Verbose is one of few logging libraries that work with threaded applications (See Comparison of Common Lisp Logging Libraries), I had some trouble getting it to work in my application. I have a Hunchentoot web application which handles each request in a separate thread that is built as a standalone executable. Getting Verbose to work in Slime was trivial but once I built the standalone, it kept crashing.
Sometimes it may be necessary to execute an external command that takes a long time to complete, long enough that the user needs visual feedback while it is running to show that the process is still alive.