EU referendum, brexit and the aftermath

Not even close.

People even write articles about how some petitions have been successful. http://www.huffingtonpost.co.uk/2015/06/22/changeorg-successful-petitions_n_7635750.html

Of course the link between petition and outcome can be pretty tenuous. But just because you can't prove that a petition actually directly and individually led to it's intended result, that doesn't mean it didn't achieve anything.

Take a look, for instance, at the change.org petition to the Canadian Government on banning microbead plastics. The Canadian Government itself doesn't recognise petitions. However, the level of support that the petition garnered was enough to prompt politicians to start looking at the research around microbead plastics and come to the conclusion that they deserved to be banned on environmental grounds. The petition itself didn't achieve the ban, but it got the right people interested in the matter in the right way that led them to want the outcome that the petition was asking for. I would count that as a success.

Of course, as The Guardian rightly point out, petitioning through DirectGov is an easy way to throw your own campaign under the bus. If you're savvy then you can use a petition to back up your campaign and press home a political advantage to bring about the type of change that you're looking for. That's how you get a petition to achieve something.