This tech stock's AI-driven momentum is getting harder to ignore.Investors looking for a top stock idea with long-term exposure to AI (artificial intelligence) often start with the chipmakers. But the bigger opportunity may flow to the platforms that already sit on top of the internet's most valuable attention and data.That's why Alphabet (GOOGL 0.54%) (GOOG 0.51%) deserves a closer look today. The tech company is still best known for Google Search, YouTube, and its broader digital advertising franchise. Ye ...