honesty

So one of the things that really stood out at me from this afternoon's conversation was about blogs being honest or being only what you want other people to know/see about you. So that really got me started thinking about honesty and what it means. If you only reveal parts of yourself to someone, is that not being honest? I mean we often say that you have to tell the whole truth to be completely honest. But that often refers to someone conveniently leaving out information that could change the situation if it was known. Is it not being honest to not share information that doesn't necessarily change the picture? Can you be honest, especially about yourself if you don't tell everything? what exactly is honesty beyond not lying or intentionally misleading someone?