I finally decided to check in on why people type a period before the username (".@") in some Twitter replies, for example:
.@launchforum - Tell v-Gor I said "Hi"!I found a detailed overview on it here. The short version:
Twitter does not always show every tweet you make to all of your followers if they start with @username (replace username with whomever your're tweeting with of course).
So if you want everyone to see the reply you are making, adding the period "." just before the "@" symbol will trick Twitter into displaying your tweet to everyone that is following you.
Well... it will show up in their stream depending on which Twitter software they use, and how closely they're actually watching. =)