Londoners are becoming keyboard warriors to express their unhappiness with Transport for London's (TfL) decision to revoke Uber’s licence to operate in the city.

Since the news on Friday that the cab-booking service's licence would not be renewed (September 22) more than 700,000 people have signed a petition urging TfL to reverse the ban. But Sadiq Khan, mayor of London, continues to back TfL’s decision to stop the driver app operating.

[Read more: Uber alternative apps]

The petition, posted on campaigns site Change.org, is the fastest growing petition seen on the site in 2017, according to Change.org’s UK director, Kajal Odedra.

“The speed with which this grew shows how powerful online campaigning can be,” Odedra said.

But are such online petitions effective? These three previous causes show online clicks do not necessarily translate into implementing change.   

Prevent President Trump’s state visit to the UK

On the UK government’s petition website, where if a cause is given 100,000 or more signatures it has to be consider for a Parliamentary debate, nearly two million people signed a petition to prevent US president Donald Trump being invited on a state visit to the UK.

Trump and May

While the visit has not happened yet, the Government did not change its mind and responding to the poll said it acknowledges the opinions expressed, but that a state visit will occur. 

Number of signatures: 1,863,708
Success rate: Government said Trump will receive a full state visit, but said it “recognises the strong views expressed” by the signatories.

[Read more: Government’s response to Trump petition]

Brexit and a second EU referendum

Unsurprisingly given the airtime and column inches Brexit has received, one of the most popular online campaigns has been about this much-debated and divisive topic.  

EU and GB flag

More than four million people signed a petition stating that the UK government should implement a rule that if the remain or leave vote is less than 60%, based a turnout less than 75%, there should be another referendum.

However, the government rejected this plea as ministers plough ahead with plans in Brussels.

Number of signatures: 4,150,262
Success rate: Not successful

[Read more: Government rejects demand by four million people for new EU referendum]

End tampon tax

Change.org gained more than 300,000 signatures for its campaign to axe tax on feminine hygiene products.  

The demand led to Parliament accepting a tax amendment, due to be implemented by April 2018, and major supermarkets cutting prices of affected items before that final date.

Number of signatures: 320,089
Success rate: Success