without reading what the other peeps have said a dried yeast comes as a dry powder, yeast comes in several forms, the most active is in the form of a liquid, which is very readily added and very active the down side is, that as it is already liquid its shelf life is very short as because it is active it is growing, once It has out grown its environment it dies fast, as opposed to a dried yeast which, can be stored for long periods of time and once active gets more active, and there in is the difference. dried = longer storage, liquid more active = shorter shelf life.
Apart from marmite, which is a yeast supplement any active yeast should grow in the right environment.
As a general rule home brewers want/need dried yeast, which preserves for a long time and becomes active when needed and is the correct choice.
Yeast which is moist and active survives best under fridge type conditions as it slows down yeast activity, hence longer life, dried yeast survives best under cool to moderate room temps in a dark environment (ie) a coolish cupboard, in a container, which is well wrapped and which prevents moisture from reaching the yeast.
In short dried yeast survives for much longer periods, active yeast which is moist and which must be kept in a fridge, only survives for about 7 days or so and in the uk, active moist yeast, is more predominant in bread making on a commercial scale, as opposed to home wine making.