Google launched Google+ back in June of 2011. Facebook, in particular Mark Zuckerberg, saw it as an immediate threat to the platform. Google had a big advantage over Facebook. As it has been the default search engine on many computers, smartphones and tablets, as well as having a slew of Gmail and YouTube accounts already. Which meant users wouldn't need to do much to start using the service. When Google+ started, it was meant to be an online identity to tie together all of Google's services. Much like Facebook had been doing for the entire internet.
A former Facebook employee, by the name of Antonio Garcia Martinez, has a new book coming out this summer. And in this book he recounts the day that Google+ was announced. Stating that Zuckerberg put Facebook on lockdown. The lockdown was essentially to get Facebook ready for what Zuckerberg thought would be a war between the two. Of course, we all know now that Facebook is still king and Google+ is struggling to get active users.
The lockdown caused Facebook to start thinking twice on a code change before actually pushing it out. Martinez stated that Facebook could occasionally look like a "thrown-together, social-media Frankenstein" with all sorts of bells and whistles on the platform. That was something that changed that day, during that lockdown. Those on the Ads team basically sat in "corporate solidarity". Seeing as there wasn't much that the Ads team could do as this was a user war and not a revenue war. Additionally, Ads product manager, Paul Adams was in close conversation with Mark Zuckerberg and a few other executives. Adams was one of the product designers for Google+. So they were picking his brain for everything he knew about Google+, seeing as it had just launched, so he was able to actually talk about the details. Facebook was really going to war with Google+, as they saw Google as a true competitor to their throne.
A bit interesting to see that 5 years ago, the announcement of Google+ really threw everyone at Facebook through a loop and put everyone in lockdown. But then again, Zuckerberg is serious about the business he has created, and is looking to keep Facebook on top.