Traditional AdTech has been on a decline since the mid-2000s when Google and Meta established a near-monopoly, capturing nearly 80% of the U.S. digital ad market. In recent years, the landscape shifted dramatically with the rise of AI platforms like ChatGPT and Claude, which have created new advertising opportunities. OpenAI's recent move to test ads in ChatGPT and the rapid growth of AI startups, such as OpenEvidence with a $100M annual run-rate, signal a resurgence in ad revenue models that leverage these advanced technologies. Three key shifts are driving this revival. First, AI platforms offer a new advertising environment that goes beyond traditional social media, providing advertisers access to massive, engaged audiences. With users engaged in rich, detailed conversations, advertisers can gather unprecedented intent signals. Second, vertical AI is emerging as a new frontier for targeted advertising. Industries like healthcare are finding ways to monetize their platforms with contextual ads tailored to specific user needs, as demonstrated by OpenEvidence's approach of offering free access for professionals while generating revenue through ads. Lastly, the infrastructure for tracking and measuring ad effectiveness is evolving. As conversation-based interfaces become more common, the old metrics of clicks and impressions are being replaced by new models that assess influence within multi-turn interactions. These changes suggest a significant transformation in how advertising works, moving from a focus on clicks to a more nuanced understanding of user intent and interaction. This shift not only creates more opportunities for advertisers but also challenges them to adapt to entirely new metrics and strategies in AI-driven environments.