Soft humanity (The ones in the top left counter) also VERY slightly increases your resistances.
So someone with 99 soft humanity will take less damage from everything than someone with the same exact stats and armor but with only 1 humanity.
actually, the humanity bonuses cap at 10 soft humanity.
I swear to god this post is more of a terminology clusterforget than Homestuck and/or Problem Sleuth, and those was MADE to be like that.
I can probably explain it better.
There are two forms of humanity. First is the item, which you can find in your inventory. This is referred to as "hard humanity", because when you use it, you crush it in your hand. In the top left corner of your screen is a number. When you use a hard humanity, that number increases. That number shows how much "soft humanity" you have. When you die, you lose all of your soft humanity, although it is retrieved if you get to your bloodstain.
There is almost nothing you can do with humanity in its hard form. However, aside from increasing your soft humanity counter, it can also be used to heal. But, unless you've farmed a stuff ton of humanity, it's not optimal to use your humanity for healing unless you're desperate.
Soft humanity has many purposes. For one, it is what lets you turn human. When you die, you respawn in your hollowed form. If you look at yourself while you're hollowed, you'll see that you look like shriveled corpse. While you are hollowed, not only are some of your resistance stats decreased, but you also cannot be invaded by other players, but you also can't summon or invade other players. The only way to become human is to use a soft humanity at a bonfire. You can do this by sitting at a bonfire and selecting the "reverse hollowing" option. When you are human, you don't look like a damn zombie, and you have access to all of the online features. However, this also includes being invaded by other players. Also, you've probably noticed that, unlike all of the other bonfires in the game, the bonfire in Firelink Shrine gives you 10 estus flask uses (i hope you got the estus flask). There is actually another option you can select at bonfires that uses soft humanity. This option will increase the amount of estus uses that bonfire gives you to 10. There's also an item you can get later in the game that will allow you to increase the amount to 15 and 20.
I think that covers everything, except for the weird part of Slayer's post that had a short, disconnected guide for getting the white soapstone. However, I will go ahead and say that the white soapstone will give you the ability to be summoned by other players for co-op.