The OP will be updated with new information as soon as v6.1 goes live, later today...
In the meantime, here's a quick teaser trailer for v6.1 - http://www.youtube.com/watch?v=Jq-bWkC27lk
You'll notice a bunch of different types of goblins...these are inspired by the goblin tribes of Oblivion, as well as the lore basis for the Altmer having trained goblin footsoldiers.
I've added a new in-game book, which explains their appearance:
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Goblins of Skyrim
by Fedris Hler
Despite Skyrim's inhospitable climate, rumors have persisted of increased goblin activity and settlement within the borders of Skyrim. Intrigued by these claims, I myself set off to investigate, and here present the results of my investigation.
It was not too long before I found evidence of goblin activities - a bloody trail led to a cave with a distinct similarity to a type found in Cyrodiil - in the front of it was a totem in the form of a tribal banner.
"Dragontooth Tribe"
This tribe, so-named due to this tribal banner with a symbol which resembles the tooth of a dragon, are of moderate intelligence, and do not tend to attack unless provoked. They appear to be focused on internal territorial disputes with the other goblin tribes found in Skyrim.
"Dark Cave Tribe"
This tribe of goblins appear to be the most numerous - what they lack for in strength and intelligence, they make up for in numbers. Despite their name, they are often found scavenging around the lands of Skyrim.
"Frost Bite Tribe"
The frostbite goblins, as they would come to be known, are from the colder regions - their shamans appear to be skilled in the use of frost magic and they are highly resistant to frost damage themselves.
"Rock Fall Tribe"
These goblins are found more commonly in the more temperate mountain regions - unwary travelers can fall victim to a stone avalanche ambush set up by this tribe.
"Skull Basher Tribe"
This tribe is undoubtedly the most vicious of all the Skyrim tribes - they are highly aggressive and cruel - and should be avoided at all costs. They can easily be spotted by the masks they wear - I heard a rumour these masks are made from the skulls of slain wanderers.
"Iceblade Tribe"
Named after the enchanted blade wielded by their warchief, these goblins are skilled in the use of both long and short blade.
Each tribe has its own banner totem - I imagine that a collector would pay good coin for a complete set.
ADDENDUM:
It is well known that Altmer historically have trained goblin armies - in recent months there have been reports that the Thalmor are now starting to travel with goblin escorts. These goblin guards are loyal to the Thalmor and are well-trained (presumably they originate from the Summerset Isles) - although it is not yet known how the Thalmor manage to achieve such control over the creatures.
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All goblins have been inspired by the different looks and behaviours of goblins as found in all previous Elder Scrolls games, from Arena all the way through to Oblivion. Each type of goblin in SIC has its own unique special features, as well as unique visuals.
And yes - you can collect these totems! If the player equips a banner, a unique "Goblin Friend" faction gets added - the members of the banner tribe get friendly towards the wielder and follow him, as if he were their leader.