In DOTA 2, what is the difference between soft support and hard support?

[siakew]

i know the overall difference, but for the exact roles? in ranked all pick, should Hard Support pick first? or Soft Support? any details for it?

[Ais Wallenstein]

Hard support (pos 5) = wards, dust, sod, stack jungle, heal, self sacrifice.
Support (pos 4) = afk jungle.

[Kitler]

pos4 is playmaker, he roam/gank/help with warding/make plays

[Zagryzaec]

Pos5 - babysitting carry.
Pos4 - control condition of lanes.
None of those go farm jungle, they always have something to do on the map.

[lolotech]

from when i played carry, hard/soft support go kill stealers like zeus or lion, take all the creeps, save skills for kills, blame team for failing to win

from when i play support, throw yourselves mindlessly at the enemy and die for your carries amusement because even if enemy is 100 hp, their too busy with creeps to bother helping.

[Wacker]

Hard support buy sentries begrudgingly
Soft support cry when you ask them to ward