I think the simplest explanation is best. It is not manipulation by whales. It is the miners. The miners mine 50,000+ coins per day. Rewards etc every Friday average about 40k (so not very substantial compared to mining).  Every so often a wave of new people or existing folks with extra cash get excited and want to buy up more or buy up for the first time cause they think START is great idea. When these new people come in it is often because of a lot of buzz and things happening with startjoin and the ecosystem. This investor buying gets crowded and prices start to rocket up until everyone who wants to get in gets in. Real simple. Then we are ALL LONG but the miners keep selling (Prob not 50k per day but maybe 30K).  Price dips a little or a more short term trader sells believing it is top then this dominoes all the way down.  The coin has growing interest and people are buying with each wave of action but not enough to crush that 50k per day mining.

Good news. Around Oct 20th. the mining block reward will go from 40 per block to 20 so the 50 per day should go 25k and everything will change.