'Mana Dork', as a slang term, refers to a creature that taps to produce mana, such as a Llanowar Elves.
What is the origin of this name? If someone simply started saying it, do we know who first popularized it?
The oldest reference I can find for this kind of usage of the term "dork" is an event coverage article on the Wizards website apparently dated January 1, 2000. It contains this description:
"dorks" - creatures that are "ok" but not "savage"
This may be establishing the use of this word in this way, or it may just be explaining the usage.
The oldest reference I can find for "mana dork" is this MTGSalvation Forum post dated August 29, 2005. So, it seems likely that "dork" came first, and a "mana dork" is just a "dork" that produces mana.
I think the definition of a dork can be beneficial in our attempt to dissect the language usage.
North American informal A contemptible, socially inept person.
Often the imagery conquered up is that a dork is a creature to inept to attack, but still useful in other ways. A mana dork is a variation on this theme being an inept creature that is used to ramp into other things.
This concept of a dork is rather ironic now because playing a turn 1 mana dork is such a power play in modern that you are almost forced to kill the dork before your opponent gets to untap with it. Giving rise to the phrase... 'bolt the bird'. Which is a colloquialism for using a lightning bolt to kill birds of paradise?
I remember Brad Nelson discussing the topic that when green decks in standard are allowed to untap with there elvish mystic then their chances of winning the game goes up by anything between 20 - 40 percent.
RD has realised that this is a bit more variance than they wanted one card to have and will only selectively allow one-mana, mana dorks in standard or when it is thematically appropriate (Like the printing of Llanowar Elves in Dominaria).