As time rolls on and as more people get involved with Betfair and BetDAQ, etc, the markets become more sophisticated and also home to more sneaky people. The WOM (weight of money) method of trading (where you wait for a big chunk of money to enter the market and knowing it will move the market, you ride that train to cash-ville) has become less easy to use profitably, due to spoofers, these are people who know that people are using WOM and so try to fool them into commiting their money by putting a sizeable chunks of money into the market, but outside the current matching prices and then cancel out before they are matched, causing the market to move the opposite direction. This technique is not limited to the betting exchanges, you see it in financial markets too.
Another trick to watch out for is when markets have just reopened after suspension, you can find people putting in prices to catch out the unwary, e.g. if the prices are _ 1.5 1.6 then they may add in 17 (rather than 1.7) on the hope that someone will think they have value and select it, matching up a bet that is not what they think! I would have thought it's quite tricky to get caught out like this but I've seen these prices offered quite often, so some people must be falling for it.

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