I noticed that some people inculde themselves in "cc" when they send out an email. What is the reason for this? A quick search on google showed that several people want to learn how to be able to do this automatically.
Most people I know that exhibit this behavior is so they have an email in their inbox that continues the chain, and they can see their response in the timeline continuity of the chain. If you don't CC yourself, most email clients do not show your response, as it goes to the "Sent" folder, and does not appear in your Inbox or the same folder the email chain is in.
We tend to have multiple projects live at any given time. We use subject headers like:
[Project A]: Discussion on blah
I set up rules in Outlook where if an email contains "Project A" in the subject, it should be routed to the "Project A" folder in my inbox. When I CC myself in these emails, I can be sure that my "Project A" folder contains all related emails, including those that I sent.
It also means that I can periodically clear out my Sent Mails folder without worrying about losing project specific emails.
Some people use their email inbox (and sometimes other tools in their email client, such as Outlook's Todo list) to manage work tasks in a central location. In this case, putting emails that indicate that something requires action (a task, something to follow up on, etc.) in their inbox is a way to make it more visible than in their sent items folder. Adding a CC to themselves immediately puts the item as unread in their inbox until they process it appropriately.
I only CC myself when I need to create a "paper trail." Most of the time it is sufficient to wait for the other person's reply before I think about the thread again, but if I find that the other person is being unresponsive or if I need to follow up if the other person does not respond in a certain amount of time I will CC myself. Once I have CC'd myself it is easier to reply to myself later and anyone reading the thread later can see the gap in response between my two emails. Usually people see this happening and want to reply so that it does not look like they are the problem.