Artificial intelligence (AI) swept investors into a frenzy in 2023. It all started with Microsoft's $10 billion bet in January on generative AI start-up OpenAI, which develops the famous ChatGPT online chatbot. Then in September Amazon invested $4 billion in OpenAI rival Anthropic.But those trillion-dollar tech giants weren't the only ones scooping up AI assets. Everyday investors identified several small-cap AI stocks with explosive potential throughout the year, including C3.ai (AI -5.03%) and Upstart Hol ...