Can I ask some noob questions about the reddit minecraft server?

1. When you build something, it goes away in a day, unless you ask for it to stay?

2. If what you build is "permanent" does it stay forever on the map, or does the server wipe clean periodically?

3)Where do I go to build shit? Everywhere I go is all built up, even to the borders.

4. Where is everyone mining this shit? Every guy I see has like unlimited gold and metal, but I don't see anyone mining.