I only recently started researching it and from what I gather from the posts on this forum and the cex.io chat is that it is regarded as a daytrading platform rather than a mining platform. So people (and bots) try to buy lower and sell higher. Overall trend is obviously down because they trade in GHs and a GH produces less and less coin as the difficulty increases, so the price falls. The common wisdom over there is that people who keep their GHs for a long term lose money. It looks like the majority of users lose money. It's a weird kind of market because they are trading in hash power of one company and it's partners and there seems to be no way to short sell GHs, plus the price is guaranteed to fall.
However the GH prices over there (at least when the "market" seems to drop) are better than most mining contracts you can find. And most mining contracts are sold by companies that seem to be extremely shady.
For instance on Dec 30th prices dropped to
BTC0.035 per GH (~$27) while
http://bit-mining.co (that's one company that seems to have at least some references, probably operated by a Canadian college student) sold a
yearly contract for
BTC0.05 (~$39) and cloudhashing.com (which was recently profiled in NYT) for $1000 for 10 GH yearly, ~
BTC0.13 per GH. One mining contract vendor (that happens to be a hardware vendor as well - butterflylabs.com) is preselling $11 (~
BTC0.014) per GH contracts but they don't know when those are going to actually start working. March-April if you are optimistic, by which time cex.io rates are very likely to reach that level. At cex.io you can at least sell the GH on an upswing, not be stuck with them for a year as they become worthless. And they are actually fully operational as we speak.
I wish there was a mining contract vendor that sold contracts priced based on the difficulty or something similar to that to take depreciation into account.
So... What's a guy without enough funds to buy a rack of asics to do? Maybe mine Litecoin...
prolom.