Who is most evil on the internet? If we're to believe the latest coverage surrounding Facebook, then we'd probably have to say Mark Zuckerberg and associates, who have decided that graphic video footage of beheadings on the social network are AOK with them, so long as they come with content warnings. Bet you're missing that wanton youthful abandon of Myspace now.

Facebook's explanation for allowing executions galore on your timeline seems to be that the site has morphed over the years from mere social network into noble protector of freedom of information, no matter how disturbing the content. That's right: it's basically WikiLeaks, but with a constant stream of updates about what your old school frenemies' babies weigh. Get rid of all those boundary-pushing, controversial beheadings, and it's a slippery slope to an endlessly banal stream of boring people who spend hours carefully constructing online facades in order to convince "friends" they don't even know in real life that they go to better parties than them. Oh wait.

If you think that it's only Facebook fiddling with the parameters of morality in today's cyberworld, then you might be interested to know that Google is evil too. For those who know Google's motto, "Don't be evil", and have taken it at face value, this could come as something of a surprise. But for those of you who, like me, have a Gmail account and feel ethically torn about it but way too lazy to delete, it might not be such a shocker.

Gmail has been accused of "automatically scanning" the private contents of emails to and from your e-buddies for a while now, and using the information to tailor the advertisements it places in the corners of your screen. From 11 November, it will be widening its remit and taking "names, photos and reviews" from connected sites like YouTube to use in marketing. In other words, don't be surprised if your face and words start appearing in the online adverts that presently irritate you on a daily basis.

What all of this essentially means is that by signing up to a service run by Google, you are no longer just part of the system: you are the system. You are the advertised-to and the advertisement, the customer and the marketer, the instrument of your own drowning in commercial fodder.

But is that evil? In a recent Atlantic article titled What is "evil" to Google?, Ian Bogost argued that Google's wrongs were "evil insofar as they prevent a program from being effectively created and maintained, not because they make that program run wickedly". The company's position on not being evil essentially means a commitment to technological progression, not a commitment to morality (Bogost also points out that Wiktionary has already redefined evil in the case of computing/programming as something that is "undesirable; harmful; bad practice", far removed from what most of us might understand "evil" to mean.) Perhaps, then, not evil at all.

But if turning a blind eye is more your kind of evil, then we shouldn't let accusations levied against Ask.fm this year pass us by. The site, whose audience is mainly teenagers, was linked with the suicides of a number of users last year after they apparently suffered a campaign of vicious cyberbullying facilitated by its anonymous questioning set-up. Ask.fm's failure to monitor and protect its young users was seen at the time as the ultimate online evil: developers had built a platform that could be easily used for harassment, and then failed to take responsibility for creating such a platform seriously. It eventually changed its safety policy, but anonymous questions remain, with a company disclaimer that it "strongly encourages" users to turn the option off.

We saw the same problem with Twitter, where a particular fever pitch of vilification directed at Caroline Criado-Perez drew attention to a situation that had been going on for a long time. Twitter eventually bowed to public pressure and introduced a report abuse button for individual tweets in August, but not before arguing long and hard for its right not to do so based upon the practicalities of sifting through so much material. It wasn't the most sympathetic argument in the world: our lucrative website makes it so easy for people to abuse each other that the volume of reported material after the introduction of a "report abuse" button would make its creation horrendously inconvenient. So why not keep things the way they are?

Unsurprisingly, it didn't fly. It suffered the consequences of its own tweetstorm.

With friends like these in the cybersphere, it's hard to believe that any of us need enemies. And with your data now standing as the most valuable asset you have, there is cause to worry about exactly how evil your email account is versus your networking outlet. You might not see a beheading on Google+, but your music taste may well be gathered, analysed and sold as you type. You might applaud Twitter's new position on abuse, but be less enamoured with the idea of someone policing what you write.

Ultimately, the worldwide web is a scary playground populated with a lot of powerful bullies. The only way to navigate it safely is to scrutinise terms and conditions, monitor your privacy policies and, if in any doubt, opt out. It's a time-consuming inconvenience they're hoping you won't undergo, but it's worth it. In other words, it's a necessary evil.