1. Google had recently exploited their home page to push chrome browser successfully altering the browser market. They pushed anyone visiting Google to chrome with a popup on the home page. The same opportunity was there for G+, but with updates from friends.

2. Everyone already had a Google account and many millennials were using Google Talk at the time. It appeared Google could undermine the network effects.

3. The UI of G+ appeared better

4. Facebook had released the newsfeed otherwise known as ‘stalker mode’ at the time and people recoiled at the idea of broadcasting their every action to every acquaintance. The circles idea was a way of providing both privacy and the ability to broadcast widely when needed.

5. Google had tons of money and devoted their world class highly paid genius employees to building a social network.

You can see parallels to each of these in AI now. Their pre existing index of all the world’s information, their existing search engine that you can easily pop an LLM in, the huge lead in cash, etc. They are in a great position but don’t underestimate their ability to waste it.