Just got my first set of speakers with double binding posts (Odyssey Nightingales). I've never really considered bi-wiring and frankly don't even understand what it is, but two questions. First, here's a picture of the binding posts of another person's Nightingales which are identical to my own:

1. What's the deal with the speaker wire connecting the the positives and negatives of each set together? If you're not bi-wiring, does it still need to be there? What would happen if you took it out when wiring the speakers in a normal manner?
2. I've tried using each set of posts and noticed no difference in sound, and as you can see from the picture, there's no label designating one as primary or anything like that. Am I safe in assuming that they are indentical and it makes no difference which you use?
Thanks.