Noticed that on a few songs i was searching for, this zip file automatically turned green, meaning it was being/ had been downloaded.

Are these safe? What are they?

Sorry if its a stupid question...

Thanks in advance

It's spam. Add ShareAccelerator to your keyword filters in Setup/Filters.

Here's a sample list of keywords you can use.
It will block most of the annoyances:

15yo
16yo
17yo
1yo
2yo
3yo
4yo
afford
Amateur
Anal
ARESTRA
baku
Barely
BitTorrent
Blonde
Brunette
Buy.Chea.pMP3 (remove the dots)
casin.o (remove the dot)
crack
cracked
Drilled
dvl
efreeclub
EROTRIX
Fetish
Fisting
FTV
gay
GnucCOM
hardcore
hoddies
Hustler
ifreeclub
included
inside
ipod
kiddie
kiddy
LimeWirepro
LimeWireWin
LimeWireWinInstaller
Lingeri.e (remove the dot)
lolita
MILF
molested
Naked
nano
Napster
Naturals
Naughty
pedo
Penthouse
Playboy
pleaser
pr0nstar
Private
pthc
Puss.y (remove the dot)
raped
Redhead
ringtone
scotto
ShareAccelerator
shirts
smut
Sponsored
Strategy
Strips
Teen
tones
totally
tranny
transvest
Unlimited
Xellos
xxx
Young