Are you able to be online without others knowing?

They say you can on 1+U but I don't think it works on JSH

Not that I know of but you can block people and/or turn off instant messaging

Re register under a different name and stealth around

lol, bad idea....multiple profiles are not allowed

Log in through http://www.oneplusyou.com/

go to "my account" click "settings" click "turn on stealth mode"click "activate stealth mode"

I am not sure, if this covers JustSayHi, so you may want to verify with a friend.

**EDIT** I just verified this with a friend (thank you Keith)it only works exclusively on One+You, For instance i was logged in to both sites, stealth does not work on JSH, so you have to be logged out of JustSayHi to be in stealth mode.

How to turn off my active status on mingle 2

You will need to upgrade before you can enjoy stealth mode.