I find the whole lockbox/any agent can wander around your house thing odd in the US.
Here is OZ one agent or agency sells your house. They are the only people who show it, usually at an open house where anybody can turn up at a set time to view. If you want to view or buy the house you have to deal with them and the seller only needs to deal with that one agent who get all the commission.
In Canberra we have less auctions than Melbourne, more are private treaty sales but auctions can be popular since they apparently get you a better price. Sometimes they are on location, othertimes they are held at the real estate agency or at a funciton venue if they are doing many properties at the same time.
In Canada, sellers can choose either exclusive-listing, or multiple-listing. "Exclusive" means that only agents affiliated with that particular agency can show the house. "Multiple listing" means that all agencies in the neighbourhood have the freedom to show the house, and present offers for it.
The commission is usually lower for Exclusive - but it also means that the place has less exposure. Unless it's an extremely hot market, most vendors do choose Multiple Listing - along with the almost-inevitable phone calls that an agent wants to show the place in a half-hour... It's not fun, but it's something that most vendors have to accept if they want the place to sell relatively quickly. Open Houses are quite common here, but apparently the percentage of sales that originate from an Open House is pretty small. A lot of people who look through Open Houses are not quite ready-to-buy but are scouting out the area, and for the realtor it's good for drumming-up future business, even if not for that particular house.
Auctions here are pretty rare except for (a) a very high-end place, or (b) when the municipality is selling the place for taxes. Tax sales almost never actually happen, it's just a technicality that the notice has to be made.
The US is pretty much the same as Canada, not sure about the Exclusive vs Multiple as I've only seen Multiple. Both the buyer and the seller can have an agent, its not required but it makes it easier. I've never sold a house, but I bought mine a year ago and the process went something like this:
1) find a house you like your agent submits an offer which is either accepted or countered.
2) the seller and the buyer agree on a price
3) sign a contract which stipulates any pre-sale actions
Pre-sale items include: financing, an inspection and depending on the loan type an appraisal
4) buyer gets financing and is satisfied with the inspection (and the seller has fixed any problems found during the inspection) and the bank approves the appraisal
5) Meet with Title company, may include Lawers depending on the state
6) Sign title and hand over down payment (0% to 30% or higher, depending on the loan type)
7) Get the Keys!!
Typically the seller arranges comission for the sale and the buying and selling agent neigotiate how much each get. One thing I learned was if you go to an open house and you don't put an agents name on the sign in you automaticly have to use the selling agent for any transactions on that house. Our agent made sure to stress that.
Its a long process, it took us 3 months from the time we found the house we liked to getting the keys.