Edit- oddly enough, just before I saw your thread, I was just remarking that the (general) mood (sentiment)across bitcointalk has noticeably taken a turn towards more positive compared to the gloom of the last couple weeks. Bullish?
sentiment works like this - imagine everyone who is subject to craze buys the item subject to craze. At the point where the maximum amount of those people have bought, the price will be pushed up very high because of the demand they cause. However, having just bought that thing you are likely convinced for some reason or another that it will increase further in value. so when a price of something is at an extreme, an ATH, and a LOT of people are very bullish, that means that most demand is already expressed, and the slightest of supply to that market will cripple it (it will crash).
we are at a bottom extreme, and imo most people still think they are in for some 'cheap coins'. that is bullish. today, the sentiment is turning slightly more bullish, but this is not a sufficient contrary indicator because we are not near a bullish extreme. in this case, it is a good thing - people are realising that this is not the apocalypse.