How do chatbots make money?

I'm curious to know how chatbots actually generate revenue. Are they solely reliant on advertisements within their platforms, or do they employ other strategies to monetize their services? Is there a standard model that most chatbots follow, or do they vary greatly in terms of their monetization tactics? Additionally, are there any ethical considerations that need to be taken into account when chatbots are generating income? I'd love to hear more about the different ways that chatbots can make money and how they balance their profitability with user experience.