In addition to the information listed in Ekadh's answer: From Joel Spolsky's Kinda a big announcement (a small understatement), it says:
Prosus is an investment and holding company, which means that the most important part of this announcement is that Stack Overflow will continue to operate independently, with the exact same team in place that has been operating it, according to the exact same plan and the exact same business practices. Don’t expect to see major changes or awkward “synergies”. The business of Stack Overflow will continue to focus on Reach and Relevance, and Stack Overflow for Teams. The entire company is staying in place: we just have different owners now.
Which should ease concerns about this.