RE: smileys in formal settings. I grew up speaking Russian, which is a language that has a formal-you pronoun, and I spent most of my school life feeling really weird writing "you" to adults in emails, because it felt too friendly and rude and presumptuous. Badly-raised child! I generally don't use smileys in professional emails unless the other person has used them first or I really want to make a nerdy joke. But sometimes that policy feels weird if your co-workers in meatspace are fun, joking, informal people. Why would you limit yourself with people if you know you don't have to?

Also, I will add this link to a relevant post you might find interesting, mostly because I didn't notice this until the author pointed it out but also because I'm proud that I managed to hunt it down. (It is unfortunately not that well-written and touches on a lot of mind-killer topics.)