Twitter is a platform where users share their thoughts, news and all types of information under 140 characters of text. The platform creates a low-cost way to communicate with everyone and reach more people worldwide. Users follow each other to stay updated or to talk to specific people or groups.
Twitter is a highly public domain where everyone can see your post, as long as you don't protect your tweet. It is not like Facebook where you can hide your posts and photos from other people and restrict the viewing of only certain users. Twitter aims to share information with the public, so if you are a very private person don't want to lie to strangers, maybe a public forum is not for you. Otherwise, you can protect your account, which defeats the very purpose of Twitter in the first place.