What is the difference between a market and limit property in the MTGox API?

Question

I'm using the MTGox API to get data about historic trades.

When I run https://mtgox.com/api/1/BTCGBP/public/trades?since={trade_id}, I get the latest 500 trades since that {trade_id}.

Now I have for example these two trades returned:

Trade #1
{
    "date":1342135345,
    "price":"4.77728",
    "amount":"5107.98029213",
    "price_int":"477728",
    "amount_int":"510798029213",
    "tid":"1342135345801755",
    "price_currency":"GBP",
    "item":"BTC",
    "trade_type":"bid",
    "primary":"Y",
    "properties":"market,mixed_currency"
},

Trade #2
{
    "date":1342136454,
    "price":"4.78",
    "amount":"0.02000488",
    "price_int":"478000",
    "amount_int":"2000488",
    "tid":"1342136454726203",
    "price_currency":"GBP",
    "item":"BTC",
    "trade_type":"bid",
    "primary":"N",
    "properties":"limit,mixed_currency"
},

Note the different properties: "market,mixed_currency" & "limit,mixed_currency".

1. What is the difference between a market and a limit property? What do both mean? (I couldn't find it here https://en.bitcoin.it/wiki/MtGox/API/HTTP/v1)

2. what does it mean for a trade to be mixed_currency?

3. Bitcoincharts does seem to include all trades regardless of the limit/market/mixed currency, is this the right approach if you want to have a honest view of all markets?

Answer 1

A limit order is an order to buy or sell at a specific price or better. As in "sell these coins if I can get at least X USD per bitcoin."

A market order is an order to buy or sell at the best available price. As in "sell these coins for whatever people are willing to pay right now."

Not 100% sure about this, but I believe mixed_currency means the buyer and seller are using different currencies. If you buy bitcoins using EUR from someone selling for USD then MtGox will do a conversion.

And yes, the best view of the market would be with all trades included.