What it means is that some person or more likely orginisation artificially increases the price by buying up, and just when everyone is getting all excited about the price rise they dump (in todays instance about 4mill shares in one go) so that we then have normal human behaviour, and others follow suit, thereby giving the manipulators more opportunity to accumulate at lower prices.
The other way that it is done, is by artificially caping the price. I guess that as long as there are people who are willing/scared enough to let go then this is what will happen.
By the way, I remember back when SDL was at circa 9c about 25mill were dumped in one go, the price then dropped to 7.5c and then rose to around about 19c. Yep, some do win because others lose.
SDL Price at posting:
15.0¢ Sentiment: Buy Disclosure: Held