If we both like it, we can send it to more people.

For example, if you send me an invitation to speak at a conference and I ask what the topic is, you might reply with just the topic, snipping out all the details of the conference.

Every second of our lives we send and receive information.

Yes, you can discover a method you have never heard of before and send it some data and hope for the best, but that is not a good idea.

Signals can be generated by the process itself, or they can be sent from one process to another.