Recently I've seen young people not experienced in these lesser known institutions of thought wondering if they even belong here. They feel some sort of desire, but lack the knowledge they think is necessary to assess if this desire is not in vain, and so to save those that should ask their time, I have provided below a form of an answer one could expect to whether or not they belong to The Cult of Cthulhu. I've spoken with the Purveyor, and I can provide to my fellow Cultists and future Cultists what I believe to be honest and sound reasoning:
[Let us] swiftly disrupt any ignorant assumptions that can be held in the youth.
Theistic Satanism is not "cool."
Blood Cults are not "cool."
The Cult of Cthulhu is not "cool."
What I mean to say is, should you wish to join than you must be joining for the right reasons, not because you think they are "cool" and that being active in these institutions might make you seem "cool" or stand out from the crowd (I do not mean to suggest that's why you display interest, I am only laying down the premise). If you are to even think of joining such institutions, than you must do so with the mindset that these are the philosophies you share with like-minded individuals; to simply want to be a part of them because you think they're "cool" would be incredibly disrespectful, both to the institution and those practicing in it. Think for example an atheist converting to Catholicism not because he has some sort of revelation and now believes in God, but because he's seen "cool" people that are Catholics and is just going with the trend. Another example, the immature adolescent often think to go against the grain of ethics or social norms is to automatically become "cool," and so those with that mindset might feel inclined to worship Cthulhu because either few else around them are or because "Cthulhu is a big bad evil monster and that's cool." This is ignorant [both] because of the previously stated reason [and] because it shows ignorance in understanding. Cthulhu is not a "big bad evil monster," [simply] because he cannot be so simply classified - his moral compass [is] amoral and goes beyond the extremely simple ethics of good and evil as has been conceived by man. This is not a genuine reason to consider joining.
If you are sure your interests are genuine and not the result of adolescent psychology - that is to say, the battle between wanting to fit in while also wanting to stand out - than you must think if you even belong to the Cult. Some chose to see the Cthulhu Mythos as exactly what society regards them as: fictional stories that at most might be able to tell us about ourselves and our opinions on existence and the universe. Others see them as what the stories themselves say they are: "Of course Lovecraft got the idea for Cthulhu in his dreams - BECAUSE CTHULHU COMMUNICATES HIS EXISTENCE WITH MEN IN THEIR SUBCONSCIOUS." Whether you choose to believe in a physical or philosophical existence, it does not matter; just know that so long as the universe is truly infinite as it's believed to be, then there is an equal likelyhood in either belief.
The one thing that is truly consistent, however, is that those that truly belong are those that have beared Witness to the Call - Those best fit to answer the Call in this cult are those that actually hear it; you shouldn't need to ask whether you have heard the Call or not, as you will already know or have known your whole life. To quote from the works describing who are worthy to bear Witness:
"...The Worthy often feel misunderstood. They feel other people don’t see the world the way they do, that they are different from everybody else. They crave not only deeper meaning but deeper understanding too. To be part of something larger than oneself and to attain a higher sense of self. To become the perfect version of themselves. They are drawn to the idea of transformation where others around them seem satisfied with the mundane. They sense they are meant to be a part of the elite few that transcend this mundanity and see through the Illusion everyone else is sated with. They know that they are meant to be larger than life, to attain a state of being no one else can achieve and to rise above the current perceived reality..."
 Note that this mentioning of becoming "part of something larger than oneself" is not to be confused with the above-mentioned joining because joining is "cool."
If you have heard the Call, if you have beared Witness, then you should already know if you are Worthy. In a way beyond the plight of the simple five human senses, you can inexplicably feel the Call within. For many, the fact that they made it here, that they have read these above words or have read the Mythos and felt connection is proof in it of themselves that they have heard the Call. If you can safely say you wish to join not because you think it is a "cool" fad and especially if you have beared Witness to the Call, then you are more safely on your way to initiation and Ascension. To truly understand the beliefs of this institution you must not just know, but understand and accept the statement that has been proposed in Lovecraft's Call of Cthulhu - a philosophy that's been dubbed "Cosmicism," and states not only is reality infinite, but it is without a creator or divine presence. So not only does this mean Cthulhu or Az'aodrrax or Dagon are not gods but simply extradimensional beings of great power, but this means humanity. is. small. Not just physically small in the way people often ignorantly say they understand, but so small that the intergalactic play around us has been happening unhampered long before we were ever spawned by mistake or as a joke, it is happening unhampered now despite humanity's own interactions, and it will continue to happen unhampered long after we are gone. As I've quite simply put it in my own works, "The Universe and it's contents have always and will always belong to those that can truly shape or influence them, in such a way that "those" will never mean us. This was never our reality... we are just living in Theirs." As it has been said in the works here:
"In most belief systems man's significance in the universe is validated by his connection to divine agents with similar moral values. This is a fallacy. Common human laws, interests and emotions have no validity or significance in the vast cosmos-at-large."
Your typical school guidance counselor or family-friendly television show will tell you that every life matters and is unique and special, and perhaps that is true, but it's only true in our tiny little bubble; the universe will not care if you are alive tomorrow. You could be the most honest and caring individual to ever be born, and the universe still might just decide to kill your daughter in a car accident tomorrow - OR IT JUST AS LIKELY MIGHT DECIDE NOT TO. If you are the type to view this as pessimistic, and even depressing, and you hate the sound of it, than this cult is not for you. But if you are the type to view it as we do, that it's not pessimistic but rather realistic, and you are capable of accepting this fact of life despite perhaps finding it terrifying, than you may be one of us. To take from The Mad German - which is to reference the one who's work likely influenced and molded Cosmicism, Friedrich Nietzsche - we must take this understanding and acceptance and use it to obtain Ascension, the truest pursuit of this institution, and use what precious time and relevancy we have to pursue perfection. We forgot all we thought we know and learn to accept what is true. We live in a constant state of realism, and we will continue to pursue Ascension until the universe decides we are done.
So there is my answer. You know your interest is not in vain when you can observe our principles not with that sort of immature/emo/snowflake/rawrXD/egocentric view but with one of mutual understand and connection. You know if you belong to the Cult because you have beared Witness and heard the Call. You know you belong if you can accept and understand without ignorance the meaning of Cosmicism and how it is applied in our everyday (pathetically small) lives. If These traits apply to YOU... than welcome home Brother. Iä Iä, Cthulhu fhtagn...
This response has been slightly modified for the purpose of being reposted here. The original response can be found as a comment on the post "Young Blood Cultist" by user Liam Roan Huxley on October 11, in the Welcome folder of the forum.