I understand the purpose of up-voting or down-voting a question or answer. But there is another option for the questions i.e., marking a question as favourite. I don't really understand what purpose it serves. As far as I have searched, I could not find any explanation as to what it is used for. I know that this question does not belong to Electronics SE alone but to the entire SE network. But can anyone here enlighten me about the use of marking a question as favourite?
Unlike voting, which is for the system and everyone else, marking posts as favorites is for you. Go to your user profile, and you will see there is a "favorites" tab. Stuff you mark as favorite shows up in this list. This is basically a way for you to make your own private list of posts kept for you by the system.
There is one side effect seen by others that I can think of. The number of users that have marked a question as favorite is shown by that question. Possibly there is a rep threshold to be able to see the number of uses that marked a question as favorite; I don't remember.