Principle for engaging skeptics: only address objections you have a genuine, thoughtful answer to; answers in public forums may serve lurkers more than the person being addressed.

Winger's advice: only respond if you have a good, honest answer — one you'll stand behind later. Don't engage just to engage. Also, in public (online) settings, the person you're responding to may not be the primary beneficiary. Many people silently follow apologetics conversations online without indicating their presence; your careful response may be exactly what a lurker needs even if the skeptic himself dismisses it. This means engaging publicly is rarely a waste of time even when the direct interlocutor is unreceptive.