There is a real problem in teaching someone lisp, when they had no prior experience with functional languages and too much experience with imperative ones.

You need to rewire your brain and think differently.

Which is probably the exact reason why it is so highly recommended that you go out and learn it, even if you'll never write a single LOC in it professionally.

I don't know much about common lisp (compared to scheme) but pretty much every bit I have seen (which is not that much) has nothing to do with functional (in the "strict" sense). I would think it would be easier to pick up then say haskell, in terms of the "head adjustment" factor (which is also a bit of a bogus argument, anyone who would have an interest in working on a startup using CL would surely have spent some time in functional land anyway).

You're right.

Here's a complete database-driven web application in Scheme:

http://brlewis.com/map.brl

Try the "Show Source" link there.

The same language is in use at my day job. When we hired somebody else to work on it here, he was writing production code his first day. He left to work for the Obama campaign. Someone in house with prior PHP experience took over, and likewise was writing acceptable production code in a day.

great example.

"but pretty much every bit I have seen (which is not that much) has nothing to do with functional (in the "strict" sense)"

CL is the ultimate "multi-paradigm" language. You can program imperatively to your heart's content with progn. CLOS+MOP is perhaps the world's most advanced object oriented system. Meta-programming taken to what would be considered absurd levels in other languages with defmacro.

Now, your code will flow more nicely if written in a functional style. But you are definitely right that CL does not restrict you to functional programming.