I used to be invisible because I liked looking at some pretty old threads, and then I found that not long after I viewed it, that thread would get bumped. So I assumed that the newer members would look at the users online list and see I was viewing an old thread, and then post it in, not knowing it was dead. So then I went to invisible so that this wouldn't happen anymore, and it seemed to stop.
As for others, I'm pretty sure the staff members use it just to be sneaky ****s, and the rest of the members just use it because they don't like publicly announcing that they're online.
It's because when you are not on invisible, people will see you online & expect you to answer right away. Sometimes I don't want to answer, but I swear these people stalk your activity. They come at you with "Wdf why did you do this instead of answering me".
Also I can answer their messages whenever I want, because they'll never know I'm online.
Also it's because I can slip in & out of threads and create tags without people seeing me view the thread.
ALSO it's because I don't want people to realize how often I am on these forums.
Also a lot of the staff members like to put themselves on invisible and sometimes I want to feel like a staff member so I just put myself on invisible like them. It's the closest I'll ever get to feeling like a staff member here. Plus it makes me feel like I have a special relationship with them because only they can see me on invisible mode.
Because I used to get sent tons of PMs from new members wanting to visit my town in NL, these PMs only seemed to be sent when I was online and some people wouldn't take "No, I don't know you well enough to let you in my town" for an answer and would just keep begging to visit me :/ (I don't know why they went after me, I'm not a very well known member here...)
I've kind of just stuck with being invisible, nobody has really said anything about it to me before and it helps me avoid unnecessary PMs
The "add me"messages is also a reason why I prefer to be invisible. I used to have someone in my PM box with a few posts who kept "shouting" ADD ME NOW!! eeehm, no