[NiloCK]

A stan is a supporter/booster of whatever. I do not remember the origin.

Pol here is abbreviated politician.

[csallen]

Comes from the Eminem song Stan, about an obsessed fan named Stan.

[EA-3167]

It's also a portmanteau of "Stalker" and "Fan" allegedly, although my first awareness of it was the Eminem song you mentioned.

[javascriptfan69]

from the eminem song stan (also possibly from super-fan)

[HDBaseT]

Where's the "T" come from?

[mcv]

'T' is the second letter of the name 'Stan', the obsessed superfan in the song.

[advael]

I had heard the folk etymology "stalker fan"

[orta]

It's a reference to the name Stanley, 'stan' is the signature at the end of letters being read in the song

[dullcrisp]

Stanley is a toponymic surname, a contraction of stan (a form of "stone") and leigh (meadow), later also being used as a masculine given name.