What happened to it?
In the 1990s and early 2000s it was hard to find an internet community that didn't have a set of guidelines for etiquette that was enthusiastically peer enforced. Maybe I was just very lucky as a teenager, but it seems unlikely, given that most of my internet life concerned playing computer games or discussing computer games with other addicts. Gaming communities are now amongst the worst offenders in terms of behaviour.
These days we see news of kids hurting themselves following their experiences online. I think it's pretty foolish to blame the online abuse for the whole of this situation, just as it is foolish to blame media violence for mass shootings, but there are clearly vulnerable individuals out there who do not have the resolve to shrug of a wound of this nature. Thanks to the pervasiveness of connected communications the situation is exacerbated by a lack of escape from the trauma.
This kind of thing surely happened in the good old days that I recall, but I am certain that as use of the internet has spread so has the proportion of bad behaviour increased. It must still be only a small number of individuals, but numerous enough that they are emboldened to spout their bile without the worry of being isolated by the backlash. There is always another troll to lend validation to their hate.
There is another difference in online communities that has empowered the trolls. In those earlier days of online communities the websites, forums and chatrooms were community-built. There were exceptions, and a handful of businesses capitalising on the trend (IGN springs to mind) but on the whole a community site for a given game was hosted by a fan, and conduct was moderated by the entire community and enforced by a handful of fans that were granted sufficient permissions. This tends not to be the case anymore. We aren't empowered, perhaps wisely, to moderate each other's voices. A developer will host their own forum for their latest title and it will be policed by their paid community relations staff who cannot be as omnipresent.
In other cases there is simply no moderation, a situation that has landed Twitter in the public eye recently. Twitter now plans to allow users to more easily report tweets that cross the line. A little bit of peer moderation that has been reintroduced but already abused.
Over the course of 15 to 20 years the internet has changed. While there is benefit in peer moderation the large numbers of individuals in any given community with the benefit of anonymity allows for such a system to be used offensively. I don't think we can rely on being able to stop or filter out the contents or the contributors that we find abhorrent. While nobody should have to suffer online abuse it is an inevitability of putting yourself out and standing up for the things you believe in or enjoy. We can help each other to build the resilience needed to weather abuse (online or otherwise) and we can continue to educate each other on the values of respect and honesty. We can make this situation better, and hopefully prevent the deaths of our vulnerable young people by instilling them with wisdom and judgement. I doubt that we can ever 'fix' the problem altogether however.