Tartuffe is first and foremost a comedy. It's a farce. It's meant to poke fun at certain aspects of the human condition – in this case, it looks at how easy it is to get duped by someone who is selling salvation.
Fear mongering for profit: This is often seen in religion (the scandal surrounding Jim and Tammy Faye Bakker comes to mind), but also in so many other aspects of today's world (education, health, financial management, crime prevention…). The play serves as a cautionary tale – we can all be vulnerable, no matter who we are.
People aren't perfect: Orgon is a respected war hero, yet he falls prey to Tartuffe's flattery and trickery. Tartuffe himself is a religious leader, but he is a victim of his own greed. The play can serve as a reminder that we all have strong and weak points.
Gullibility: What makes Orgon fall for Tartuffe's lies? Cleante thinks that Orgon is particularly vulnerable since he returned from the war. Tartuffe's flattery seems to endear some people to him more easily than others (including Mme Pernelle). Others, like Cleante, are resistant to it. But why? The play helps us consider this question.
Strong female characters: Elmire loves Orgon despite his current gullible state. She is strong when she resists Tartuffe's advances, and when she sets out to show Orgon that Tartuffe is a hypocrite. Mariane resists her father's order that she marry Tartuffe and chooses love for Valere over her inheritance. Dorine is also a very strong female character, and one of the most interesting and engaging characters in the play. She has a lot of influence over everyone, and doesn't hesitate to speak her mind or interfere in the family's affairs.
Religion: The play could be seen as a commentary on blind faith and on how important evidence can be to decision making. Orgon is duped by Tartuffe, even though people whom he trusts and cares about are warning him to be careful. Mme Pernelle, at the very beginning of the play, warns the young people in Orgon's house about their sinful ways, and is the last person to believe that Tartuffe is not who he says he is. Blind faith can lead us astray.