Offlist help

It is encouraged to reply onlist instead of offlist as much as possible.
This helps the community at large to gain knowledge.

However it is understood that some people sometimes reply offlist due to
their employer being overly concerned about the amount of time they spend
on list email. Regardless of your opinion about their employer you should
respect their decision - after all, you are not the one who will feed their
children if they should lose their employment.
In this vein, thanking someone publicly who replied off list could end up
being very detrimental to their financial well being. That is generally
not the intent of a thank you.