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U.S. consumers see a minimum of around 4,000 advertisements a day, according to one estimate. Perhaps it’s no wonder then that ad-blocking software is becoming ever more popular.

But without advertising revenue, much of the content you want to see on TV, on the web or even in a movie theater would either be unavailable or priced higher than it currently is. How do content producers fight back?

Some, including online magazine Salon, allow consumers to read articles if they are willing either to turn off the ad blocker or to let Salon load a piece of cryptocurrency mining software called CoinHive on the users’ computers.

According to a BBC report, Salon displays the following page when it detects a user who is blocking ads:

Source: BBC.com

Salon tells its readers, “We intend to use a small percentage of your spare processing power to contribute to the advancement of technological discovery, evolution and innovation.”

What does that mean and how will it affect you if you choose this option rather than turning off your ad blocker?

CoinHive is one of many software tools that cryptocurrency miners use to mine for digital currency. Mining for cryptocurrencies essentially means being first to verify a transaction by tracing it through the blockchain. To do that requires massive computing power, and one way to generate that power is to network hundreds or thousands of processors to do the required math.

CoinHive is designed specifically to mine for monero, a cryptocurrency similar to the better-known bitcoin that is used to conduct anonymous transactions. Salon claims to activate CoinHive only when a user gives permission and while the user is on the Salon.com site. But the software has other, not-so benign uses.

Not all sites are so candid about what they are doing. Computer security firm Check Point has noted:

Ad-blocking software, stemming from users losing patience with excessive pop-up and banner advertisements, has been slashing many websites’ advertising revenue. Those websites are turning to crypto-miners as a new source of revenue – often without the knowledge or permission of the visitors to the website. Similarly, threat actors are turning to crypto-mining malware as a new way to make money – illegitimately gaining access to the users’ CPU power to mine for their own cryptocurrency – making it even likelier that we’ll see this trend gain steam over the coming months.