"Sinister: wants to kill herself, but worries about being grounded and losing stuff she's been doing on the computer."
After so many failed attempts, planning ahead for the next failure doesn't strike me as too weird.
"Can Sin be for real and not just talking about suicide because it's edgy?"
Has Sin showed a tendency or pattern to post plainly for that motive?
"Also, what I find interesting is that before the suicide drama started she had been for months on this site not mentioning suicide once. Then suddenly that's almost all she talks about."
Do you think that suicidal people are always that way, from the start? 
"To me, all these "failures" are speaking volumes, as is considering the next attempt a failure from the start."
Failures do happen in genuine cases. Often because attempts are in the heat of the moment, and not well planned. Or because survival instincts kick in. A person can consciously want to die, but be prevented by simple reflexes. I'm not saying this is the case with Sin, but failed attempts don't really prove anything.
"It's not unlikely the attention she gets here fuels the suicide thoughts, the way she talks about them, the way she fucking took a pic of her sticking smth in a socket (I mean come on, who the fuck does that in the middle of an MEANT suicide attempt, it's like someone throwing themselves off a building and thinking of taking a selfie in the air and posting it on instagram). I dunno, something in my gut feeling tells me there's smth else that motivates sin with her posts here."
It's a very fair point, but I suspect it's a case of conflicted feelings. It's possible that Sin both does and doesn't want to die. I imagine the impulse is genuine, but that she's not entirely resigned to it, at this point. Hence the mixed signals. She doesn't really know what she wants. However, that doesn't make the suicidal feelings less real to her.
"You don;t find the abrupt switch suspicious?"
Not at all. I assume Sin was depressed before she was suicidal. She did always show signs of that. So it wasn't really that sudden. Her condition just worsened. And that can happen abruptly and rapidly. Especially if she's susceptible to seasonal affective tendencies, as so many people are. If she survives the winter, we may see a marked improvement in spring. Even if the timing is happenstance, people with depression are rarely consistent. They have ups and downs. Sin is obviously going through something right now. Which, especially at her age, is natural. Not logical, but natural. And hardly uncommon. The way she's displaying seems very much like real, serious depression. Whether she wants to die or not.
Most suicidal people just want the pain to end, not to end their lives. I believe this is Sin's case.
No suicidal person is less suicidal just because they don't use lethal methods. Dying is painful. The best way to thoroughly commit suicide is to not let your body take control of the situation. Popping a thousand pills or tying yourself to a block of cement and throwing it down the river are one of the many ways your body can't submit to the survival instincts.
I find myself double teamed by you two again haha. I understood some of your points, you may be right. I confess I am not an expert, although I know depressive people, people with seasonal affective problems, and someone who killed himself (not too close though). They don't strike me similar to Sin, but maybe people online open up differently.
I have trouble understanding how killing yourself can fail, if you really want to. Hell they've written books about it even. The body listens to the mind if the mind is determined, but no sane mind can be fully determined to kill itself. It's a shame really too see that some shitty brain hormone imbalance can cause such ideas and such suffering, while other people want and love life with all their might, but die in stupid ways.
"To me, all these "failures" are speaking volumes, as is considering the next attempt a failure from the start."
They don't for me. According to a variety of sources, for every 25 attempts only one succeeds. It's also reported that many who try to kill themselves and fail will typically try again at a later point. The supposed statistics are pretty interesting, speaking not for how much people actually want to live, but more for how difficult offing yourself truly is (and how many succeed). It's not a matter of desire, it's a matter of difficulty.
My own attempts have been thwarted from the question of "What if I fail" before. Surviving a suicide attempt can leave you far worse off than you started depending on the means that are taken such as broken limbs/paralysis, fucking up your metabolism, organ problems, etc. Failure is less final than success, and said failure carries consequences that have to be dealt with.
"There is no real desire or intention to off herself. I think it's true in your case too Turn."
It's harder than it looks. The body, the nerves, they rebel even when the conscious mind is more than ready. It takes a high level of self discipline (or a lot of passion with a lack of inhibition) to succeed.
"Like obsessive ideas, or intrusive thoughts. You have ocd, sin is autistic and seems ocd too."
It's closer to the suffering that can be brought on from such things (among others). The view of the world is through a drastically different lens from person to person. Death to some is simply a means to an end, a way to make said suffering stop in the name of endless sleep, but it being simply that doesn't make doing something about it quite as simple.
"Remember how she was with Linux."
That struck me as a forced meme brought out from a lack of other interests more than anything.
"I was surprised when I saw in a screenshot of hers about 7 private chats. I think it could be a cry for attention, her "special thing", you know."
That could be to throw people off, opening multiple private messages, or it could be like the time she messaged me something like the word "CATS" over and over. 
"it's like someone throwing themselves off a building and thinking of taking a selfie in the air and posting it on instagram"
That'd be a pretty crazy photo, come to think of it. The motion lines and the backdrop would be pretty intense, and those viewing it would likely find a variety of ways to be haunted by it.
"You don;t find the abrupt switch suspicious?"
Not really. Maybe I've just known too many suicidal people, but said "abrupt switch" is usually how it appears. It also is rarely as abrupt as it appears, instead simply appearing that way from letting that piece of themselves become known. Once it's out it can sometimes be hard to stop talking about it from the difficulty mostly being behind the first mention of it more than anything. Talking about wanting to die is usually a cry for help, but a lack of talking about it doesn't mean that they were okay before.
A surprising amount of people on some level want to die.
"I dunno, depression isn't exactly like food poisoning..."
It's socially contagious within the human condition, so it's more like a creatively applied plague.
"Sin turned almost over night from nerdy linux sin into sin who posts suicide stuff all over now."
Something about her older posts made this "development" less than shocking to me.
"They don't strike me similar to Sin, but maybe people online open up differently."
Just how there is variety between people in general, said variety also reveals multiple ways of going about a death wish. There's self medicating and vice seeking to try to shut out those thoughts, there's daredevil activity in the form of adrenaline chasing where they're more than content with failing, there's aiming to take it directly through suicidal acts, be those acts passive (pills) or direct (self-harm), there's aiming to simply ignore/bury it as stress builds up and leads to all sorts of transference behaviors or disorderly behavior surfacing, there's those that chase distractions or drama to try to have enough noise to keep those thoughts quieter, there's the more communal types who go to others in an attempt to find answers while pre-convinced that it's hopeless despite the efforts, there's the opposite of the communal type where they try to shut everyone else out to spare them (or themselves) the pain, there's those that try to spread the "love" in ways that make others' lives worse, there's the suicide-by-cop (or other antagonist) types, there's those who bandage themselves with hobbies or collecting...
It has a variety of expressions. Life is about toil, a buildup that makes the silver linings more flavorful, but not everyone experiences those two states in quite the same ways. Impression, repression, and the lens of experience can make for many deviations between people's responses to their own suffering to the point of suicidal tendencies surfacing even from people who weren't pre-wired to be depressed.
The natural state of a person is suffering while joy and stimulation themselves are the aberration. When that is flipped for a person their joys and comforts themselves become their suffering, a prison in it's own right with boredom and a developmental tolerance against that which we enjoy as it's proof. We can suffer endlessly while we can only enjoy ourselves for so long.
"I have trouble understanding how killing yourself can fail, if you really want to."
The need to survive is one of the strongest urges hardwired into us. It's why cowardice is a thing, it's why hoarding is a thing, it's why many behaviors expressed by people are a thing. Suicide's not a matter of mere want, it's conviction marrying up to hopelessness and/or despair. Unless it's done in a reckless fit of passion, it takes some practice, a lot of thought, and a certain level of detaching from yourself to go through with it.
"no sane mind can be fully determined to kill itself."
Would you say a martyr is insane?
The only real difference lies in their beliefs.
"It's a shame really too see that some shitty brain hormone imbalance can cause such ideas and such suffering, while other people want and love life with all their might, but die in stupid ways."
Nurture can do it too, and many on the "love life" train are the sort to try to run from their problems. Many who survive such things do so through methods of delusion, escapism, vice-seeking, distraction/magical thinking, being sheltered, etc. Aiming to dispel people's coping methods tends to increase how blatant their suicidal ideation is significantly.
Depression is a natural thing, one that some need to hit to reach deeper epiphanies, a process that helps people understand that life is pain but that you're supposed to truck through it anyway, to jade themselves against the inevitable grievances and develop a tolerance. It's a part of growing up and becoming real. Sometimes though the trauma can be more than they're ready for, leading to scars that outlast the events themselves. Of course there's those more pre-disposed to said scars and even some born with scars, but it's not merely just those who suffer. If anything, a person with a lack of suffering whose means of that isn't through said methods mentioned above is the real rarity.
Everyone's running from something. The suicidal ones are those who found themselves too exhausted to keep up the pace. Most who manage to keep running typically are doing so from a form of compensation.
"(...)the way she fucking took a pic of her sticking smth in a socket (I mean come on, who the fuck does that in the middle of an MEANT suicide attempt, it's like someone throwing themselves off a building and thinking of taking a selfie in the air and posting it on instagram)."
Best.
Have you ever played the Cookie Clicker game before?