This is not a coincidence...someone is sabotaging BC for whatever reason.[/b]
It's more likely to be a large holder waiting for sufficient liquidity to be available for them to cash out.
These alt coin markets are tiny. Look at the order book. It's all decimals of BTC that are on there. There's no liquidity to speak of - unlike, say BTC-e Bitcoin and Litecoin markets. That's why exchanges like BTCe don't bother with other alts. The volume in the mainstream coins is huge - pros that trade 50-100 BTC at a time.
If you have even 1 large holder who has a lot of BC wanting to profit take, you'd see exactly the pattern you've observed: wait for liquidity to emerge, cash out a load, then wait another 10 hours or so for the bid side to "recharge" itself, cash out again, rinse and repeat.
I don't think there needs to be any conspiracy associated with it - and even if there was, they'd still need to have the BC to be able to place the order so there's no material difference to what I've just described.
There are 75 million BC's in circulation. That is quite a large amount. It means that BC is already at a tenth of Peercoin's price corrected for coin supply. So even if it got to Peercoin's valuation it would only be a tenfold gain from here whereas the buy in required would be many hundreds of times the buy in that was needed to get this far.
Taking all this into account, it's not a bad point for a large holder to "get off the bus" since they could take the view that there's more chance of it going down than up from here. THat's what's behind those big sellwalls.
Think of a funnel with the hole plugged. It takes only 10 cc to get a 5 cm rise in water level but a 100cc to get the next 5cm rise. That's where BC is right now.
I agree.
BC is has become a day-traders delight. But that is actually good, trading brings liquidity - liquidity is absolutely required to have a mature market.
The only conspiracy to contemplate is this: trades on an exchange are not wallet to wallet. A nefarious exchange could post all the walls they want. They can trade customer coins on deposit or simply short. This is an unregulated market - they could get away with it. Not saying it does happen but it sure could - just ask any MF Global customer (and they were in a regulated market!).
If this is a concern on anyone's part do 2 things:
1) Hold very little coin at any one exchange - this increases the risk of any such trading schemes.
2) As a community make sure the volume is balanced between many exchanges. Anomalies at one exchange will stand out if multiple exchanges have statistically significant volume.
Finally many exchanges, all with volume, will allow the market to self-correct via inter-exchange arbitrage.