a cult will never be a religion... lets forget about the etymology(?) of the words for a moment, let's think about positive and negative...
a religion, whether u agree with it or not, does ppl, as individuals, and as societies, some good. If it does not, then it is a cult.
there are a few key cult behaviours, and if an organisation you are involved in behaves in these ways then you might be in a cult.
look for these signs:
"extreme institutionalisation"- batch living/group living, being given new names, wearing standard "uniforms", oppressive/contricting/unusual rules and regulations, the enforcement of such resulting in severe/unusual punishments, members fear being excommunicated/thrown out of community as they no longer have possessions or a social network to fall back on...
"guru worship"- members behave differently around guru, members believe in the infalliability of guru, members report feeling different around guru, members tolerate guru even when guru belittles/patronises/uses aggression/behaves inappropriately with women/children/other participants, members believe in the infalliability of their guru's doctrine/insights, etc, to the exclusion of what is the general consensus concerning such matters,
"social isolation"- members are encouraged to socialise soley with other members, members are advised not to participate in their usual "normal" hobbies and pursuits, members are encouraged to behave inappropriately/in ways at odds with their class/cultural backgrounds, members are encouraged to actively recruit other members, members are not encouraged to visit doctors/health professionals and instead rely on alternative treatments/practises, members are encouraged to marry/reproduce soley with members of the group, members are not encouraged to manage their own finances, members are not encouraged to acquire/maintain their own material possessions,
"mind control"- all the above, plus: sleep deprivation, insufficient nutrients/unusual diets, intense periods of prayer or meditation which members cannot be excused from even if ill or troubled, periods of prayer or meditation or study which are unscheduled and regularly last for longer than 24 hours...
..unfortunately, many "religious" organisations behave in this way, and some cults do not.
but... to bring things back to your title... by my reckoning, the JW's are a cult... they practise some features of "social isolation"- but they're not giving ppl Kool-Aid and phenylbarbitone, like Jim Jones did in Guyana. But, well, being involved with them might kill you, inadvertently...scientologists- they score quite highly, although u won't die u will become light of pocket... the moonies also score quite highly, yet the worst u might suffer here is being laughed at and being forced into marrying a very ugly partner...
my local catholic church has none of these things! result! I can come and go as I please, nobody really minds, I am free to drink beer, smoke ****, and still be acceptable in the eyes of God. Sure, they want me to put some bread in the bread bag every week, but its only loose change, it's not like they want me to go flirty fishing for jeebus and charge... because there's so many of us (sure I'm a buddhist, but once a catholic always a catholic...ha!) we don't mind if you want to be in the gang or not- there's plenty of catholics to go round, and one more, one less, no big deal. There's not a big push to buy catholic music, or catholic books, and jesus don't mind if u listen to gangsta rap so long as you give a coat to the man without and give ur seat up for the old 'uns on the bus...
cults: hard work, no reward.. real spirituality: no work, big rewards.. I know what I'd choose..