It is not advertising if someone asks for a solution and you hand them
one that is not free.  It is advertising when you tell people about
your product who have expressed no prior interest it in.

You could even say talking about some FREE program you wrote was
advertising.  I find it odd in a country that has capitalism as the
state religion there is such squeamishness about mentioning products
that cost money.

I also find it highly peculiar that the most common restriction on
software in that it may not be used for commercial purposes.  Isn't
that communist?

   I'm okay with it, but then again, I'm okay with a lot of things, so
possibly I'm biased in the opposite direction. I've opalinski make helpful
(advertisement-free) posts before, so it's not like (s)he is posting spam to
newsgroups which (s)he doesn't even bother to read or contribute to.

   The OP posted some problem, and I guess Opalinski had previously solved
this problem and considered it to be non-trivial. Perhaps it was non-trivial
enough that Opalinski felt it would take too much effort to actually fully
explain the solution. So from there, Opalinski had two options: just keep
quiet, or let the OP know that (s)he can buy a solution.

   I argue that the latter, giving the OP the option to buy the solution,
is "more helpful", than the former, not giving the OP that option at all.

   - Oliver

P.S. as an aside, and this isn't a comment on the OP at all, but I find it
amusing how often I see threads of the form:

A: URGENT!!! I need someone to solve this problem for me RIGHT AWAY! MISSION
CRITICAL!!!
B: I'll do it for 5 bucks.
A: No, I'm willing to wait for someone to do it for me for free.