I bet much BTC holders that have purchased their stake when BTC was at $0.1 and show the price of BTC at $30
dollars had the same feeling like you... WE ARE ON A BUBBLE !!!!
I hope we perform like bitcoin and why not even better?
Bitcoin was just currency. Bitshares could overthrow Forex, replace banks, and it's becoming a collateralized decentralized exchange.
All it needs to do everything we dream of is to connect to Ripple or Stellar Gateways. Once Bytemaster sets up market functionality the Gateway network should become one of the top priorities so people can actually trade real IOU's on Bitshares. Once people have that ability I would say Bitshares is as unstoppable as Bitcoin with a potential market cap in the trillions.
Additionally we can design for dump resistance by reducing the excuses people have to leave the ecosystem. If you only have to cash out to pay your survival costs then why would you ever dump?
The only people who might dump are centralized exchanges so there has to be some features or products to make Bitshares a lot more sticky to these entities. Exchanges seem to do the most dumping.
I fully believe in Bitshares and its future potential...but the current price rise has me worried about a bubble that may end up crashing hard. Is it safe to rise like this? Just need a little reassurance... 
Who is going to sell and why?
Those that expect a correction and want to speculate....
Those that lost confidence but didn't want to sell at a loss and are now profitable and thus want to exit...
...
If market functionality works couldn't they just cash out into BitUSD within Bitshares itself?
It seems users can speculate inside Bitshares so I cannot think of many reasons for speculators to want to leave unless to realize their profits to pay their bills.
So there will be people who sell some, but dumping into fiat? It might be an option but we can make it the most unattractive option by providing many better options.