Lying for fun and profit
To me, the only question worth asking about people's lying behaviors is, how are they doing it? If they're only doing it to be polite or to make themselves look better, and they're not going against any of their firmly held beliefs, it's harmless. But if they make a habit of not standing up for their beliefs, and always saying what they think people want to hear, then it can become destructive.
For an excellent book with the theme of why a simplistic view of lying is a bad thing, check out James Morrow's City of Truth.
Not that I would know anything about lying for the wrong reasons. One of the reasons I started a blog was so that I could say what I wanted to say without worrying about being political or whatnot like I do when I'm doing stuff at work. I've deliberately not emailed my co-workers about it for that very reason. If I want to say something potentially controversial I don't want to have to worry about offending someone. I'm well aware that various people such as Cameron Barrett of CamWorld fame have been fired for their online stuff. I've decided I'll talk about whatever I want, including work, as long as I'm sufficiently vague about specific clients.
The other thing I should mention in this moment of partial disclosure, is that I've never been comfortable with the spill your guts kind of web log. It just seems too Jerry Springer-esque to me. It's one thing to email a friend or at least an acquaintance some shocking email or other, but to just post it out there for the world to see just smacks to me of a perverse narcissism, in assuming the world cares about your woes, and complete lack of a normal desire for a normal amount of privacy.
It may have made a bit of sense way back when the web was mostly university types with some government types mixed in, but now that the web is a big wide-open place that basically anyone can get to, it seems like walking down a major street and blaring stuff like "I have psoriasis, oh the heartbreak" at the top of your lungs.