There are three ways "씨" may be used with the name: 박찬열 씨: a neutral and most common way of addressing, as in a a workplace, government offices, etc. 찬열 씨: an address with a private feel. His girlfriend would use it (and more rarely, his female or male friends). 박 씨: A somewhat old-fashioned address without much respect. Not recommended. * Korean language standards state that the suffix "씨" must be used with a space after the name.

just add 씨 after name ^^. 박찬열씨~ or 찬열씨~

You should familarize yourself with some common Korean surnames. 김, 신, 박, 최

In 박찬열, 박 is the last name and 찬열 is the first name. This is the way of writing Korean names (Last name, First name). In 경운최, 최 is the last name and 경운 is the first name. I'm not sure why she wrote it this way. She probably just did it for her profile, maybe to seem a bit more...familiar? Like what people are used to in English speaking countries. 씨 is usually attached to first names, although it is also attached to full names. So that is why. -> 박찬 would be the last name and half of his first name haha. It would be like writing "Lau" instead of Lauren. It wouldn't make any sense or be correct. "Re" instead of "renan". Half of a name is no name at all.