Question: Today I opened a social network and saw that one of my coworkers, let's call him Bob, posted a piece of source code of one of our projects.

The quick video is blurry, so it's hard to actually read it, but not impossible.
IANAL but I'm pretty sure that this is illegal.

There is no way that anyone else in my company will see it since no one has that social network but for me.

As I see it I have 3 options:

* Act as if I did not see it
* Talk to him in private and make him realize how potentially bad this could end up being, for him and the company.
* Report this to my boss.

**Additional information:**

This is the first work experience for Bob and he has been working with us for less than 3 months.

My question is: **How should I behave in this situation?**

I really don't want to escalate this, but if something bad happens because of that post, and my boss finds out I knew about it, I think I would be in legal danger.

Answer: 
I think the answer depends on what code is visible in the video. If it's a "Hello, World!" type fragment, some loop that's meaningless without larger context, or an implementation of a simple standard algorithm like linked list etc., I would not consider it to be a big deal; Stack Overflow is full of such code and no harm is done. Simply speak to your colleague, and suggest they be careful when posting videos of source code so as not to leak anything important.

If one can see in the video a fragment of something critical to your company, such as an implementation of a proprietary algorithm, or encryption, or user authentication, you need to act to make sure the video is removed ASAP. Where I work this would be a major security incident that must be immediately reported to the security response team and to management.
Other options:

* Mention the topic of "social networks"in a casual way at lunch and clearly state that you don't think that anything related to work should be visible in a video posted there.