Coins depend a great amount of their succes on the community behind it. A small but active community motivated about the coin can do a great deal of PR and spreading the word around as to get others involved and let the community grow. The coin in return prospers as the result of it being picked up.
A large community but inactive tells you a great deal of what is really happening, which is most likely that people saw a coin they think has potential to grow into good profit but simply are on board because they want to sell it.