So, what's your answer to the question as to how religions and cults differ? I've still never heard a particularly satisfying answer to this question given that size of congregation doesn't satisfy me.

Religions and cults are a lot like tape worm infections: the very same parasite can lead to two very different kinds of diseases, one benign and one deadly.

If you have good personal hygiene but you carelessly ingest undercooked substantive ingredients from a community with low (agri)cultural hygiene standards, you'll get an adult parasite in your stomach, not dangerous, with a few minor undesirable side effects once in a while, but benign enough that it may even go undetected for quite some time, without any contagious possibility for other people (although others amongst your family and friends may well have gotten the parasite at the same place that you did).

Now if you don't have good personal hygiene, then you may get eggs directly in your body, be a pestilent source of contagion for other people even cleaner than you are, and if/when the eggs end up in your brain, then it will cause severe braindamage visible to other people and deadly to yourself, with no easy treatment.

The bottom line: always cleanse yourself after being in contact with filth, and before being in contact with anything that may be ingested by yourself or other people.

And be sure to teach that hygiene to your kids, early on. You can't change the rest of society, but if you can change the people who count most around you. And once enough people adopt good hygiene and/or the people with bad hygiene are weeded out by their behavior (rather than being protected or subsidized by the state), the community's hygiene standards will get higher and the parasite will disappear, except for small fringe communities.

Some cults are not based around religions, but rather political, social or even philosophical ideals.

The main distinguishing characteristic of a cult that I can see, is that a cult is an organization that convinces its members that recruiting (or at least actively working in support of recruiting) new members is by far the most important thing they can be doing with their lives (usually on the theory that the cult does other things that are tantamount to "saving the world", so there can be no higher goal), and then requires them to devote such extraordinary work to this mission that it requires or causes a degree of neglect of normal personal and/or social commitments such that nearly anyone outside the group would perceive the cult member as suffering concretely and drastically. These harms go beyond whatever harm there might be in subscribing to and living by the more ideological tenets of the organization to things that may seem even instrumentally harmful, possibly including such bizarre behaviors as cutting off contact with old friends and family, sleep deprivation, pathological fasting, maintaining a schedule of such devotion that holding a demanding job or course of study becomes extraordinarily difficult or impossible, etc.

All these things are things non-cult members might do briefly for any number of reasons, but it's a hallmark of cults that these become "normal", and that's no coincidence. Cults cultivate in their members a psychological sense of continual crisis: the believer is justified in taking emergency measures on a daily basis because the cult is that important. The believer is apt to go through extreme emotional ups and downs in response, and the cult can exploit those to make the believer feel even more dependent on the cult, going from stern taskmaster, scolding the believer for his or her inadequacies, to welcoming family, forgiving and accepting the believer, and occasionally rewarding him or her. The continual crisis effort level stops the believer from asking questions like "Am I really being effective at my own goals?" or "Is the leadership really planning the best way to do what they say they want to do?", which can easily lead to questions such as "Can these beliefs possibly be correct, or are they possibly a mixture of bad and good ideas and theories?"

Most (non-cult) religions, political movements, or whatever, have at least some members who are not required to spend that much effort on the mission of the organization, such that outsiders can understand that members do not have to live in a constant state of psychological crisis merely to participate. Cults of course try to hide the rigors of membership, so they commonly present a deceptive image of the benefits of membership, such as by inviting new candidates only to the most friendly and fun activities, and by offering lots of concrete help and affection, frequently going so far as to hide and lie about what happens after you actually join.

This is incorrect. A cult need not, and so far as my experience goes usually does not involve the chance to become God. However, there are some sects of Christianity that allow for this.

Anyway, it's really creepy how cults are lurking in so many places. On the plus side, it's awesome how the internet enables better information flow from critics, so that the cults can be debunked.

The internet also allows whack-jobs to find like-minded whack-jobs and build whole whack-job communities, of course.

I've often heard that the "church" in King of Prussia that does the big light display every year at Christmas is a cult.

"There was, of course, this much excuse for me and all the other losers: that Dawkins' discovery of memes is utterly unlike anything which the history of science has made us familiar with. What scientific discovery ever looked like that? And yet there is something very familiar about Dawkins' discovery,at any rare to a philosopher: something horribly familiar,in fact. I have seen that kind of thing hundreds of times before, but where? Why,in those absolutely effortless pseudo discoveries which philosophers make, and on which their fame rests..."

"But the pseudo discovery of 'memes' invites a more specific comparison, with the real scientific discovery of genes. Dawkins, to make his 'discovery', did not need to draw upon any specialised knowledge, or to exercise either his experimental or his inferential powers. All he needed was to remember that some things are transmitted non-genetically from one person to another, to give these things a new name, and then to allow free rein to the demonological bias of his mind"

- David Stove, Darwinian Fairytales

I think Santa would look better on a St. Andrew's cross.