Slate has a piece called Gchat Was the Future of Messaging, But Google Didn’t Know What It Had. Not sure I agree with the premise that Gchat was Slack before Slack, but I did find this yarn interesting:
The first sign that Google didn’t love Gchat the way consumers did was in the name. We can talk about Gchat all day, but Google never officially acknowledged that as the service’s title or explained why it wasn’t. The company staunchly referred to the application (released in 2005) as Google Talk and the Gmail integration (released in 2006) as Google Chat or just Chat.
A gentle reminder that product names matter a lot.
[sidebar: There's a yarn in the recent episode of The Talk Show where John Gruber and MG Siegler talk about the name challenges in Amazon's Echo/Alexa product. The product is called Echo, but the activation word (and even the app name) is Alexa. This is challenging for consumers and doesn't feel very thoughtful.]