Kali entered earth during the period of rule of Parikshita. So knowing that Kali had entered he set out to kill Kali in his personified form. Then out of fear Kalipurusha went into his surrender and King Parikshit allowed him to stay at the following five places only:
Sūta Gosvāmī said: Mahārāja Parīkṣit, thus being petitioned by the personality of Kali, gave him permission to reside in places where gambling, drinking, prostitution and animal slaughter were performed. [SB - SB 1.17.38]
The personality of Kali asked for something more, and because of his begging, the King gave him permission to live where there is gold because wherever there is gold, there is also falsity, intoxication, lust, envy and enmity. [SB - SB 1.17.39]
Thus the personality of Kali, by the directions of Mahārāja Parīkṣit, the son of Uttarā, was allowed to live in those five places. [SB - SB 1.17.40]
In today's terms, it can be said that Kali lives where there is money, because money also produces the same results of falsity, intoxication, envy, etc. just like gold and also gold was used as currency in those days (swarna mudra).
Minimizing Effects of Kali
Well, effects of Kali can be avoided by avoiding the things that cause kali or where kali resides. So the next verse (SB - 1.17.41) suggests to avoid contact with the above things. Nevertheless, for Kali yuga, the scriptures state Harinama is the best remedy.
My dear King, although Kali-yuga is an ocean of faults, there is still one good quality about this age: Simply by chanting Krishna's names, one can become free from material bondage and be promoted to the transcendental kingdom. [SB - 12.3.51]
harer nama harer nama harer namaiva kevalam
kalau nasty eva nasty eva nasty eva gatir anyatha [Brhannaradiya Purana]
Hari's name, Hari's name, Hari's name only without anything other, in kali there exists no other way. There exists certainly no other way.
Kali at StackExchange
Now regarding stackexhange, kali doesn't actually reside here, it resides in the minds of users participating here. It's because, the overall purpose of the site is good, but because our minds are clouded by ego, pride, envy, jealous, biased and negative feelings that forgetting humbleness, truth and politeness we treat and act negatively.
Regarding reputation, it's not actually quite gambling, but if it is considered as the currency or money of the users of stackexchange, then certainly Kali is present here because for the love and want of reputation users are doing smart things. Secondly, when Kali means quarrel, any type of subjective argument and dis-argument with negative intentions in the mind certainly proves the existence of Kali. So your assumption is right.
But even like the Kali yuga has certain merits, so also participating on SE has. Casting aside all the negative feelings we may have to endure, we do learn many things. Although with users acting politely, a site like this could be a pleasant experience, the unpleasant experiences give one the opportunity to test out his tolerance and virtue.