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A Closer Look at Reddit Vote Manipulation About Bitcoin

Adoption & community - A Closer Look at Reddit Vote Manipulation About Bitcoin

The r/Bitcoin subreddit has increasingly become a major source of news and information for anyone interested in Bitcoin. Established in 2010 and counting more than 170,000 subscribed accounts today, it is the oldest and biggest Bitcoin-related page on Reddit, and perhaps even the most influential Bitcoin corner on the Internet.

But since last summer, r/Bitcoin has been under increased scrutiny. In a controversial move, the subreddit’s moderators banned the promotion of software clients programmed to break with consensus. While many considered this a form of censorship, the moderators maintain that promotion of these clients is a risk to Bitcoin as they could split the network, and therefore it doesn’t belong on the subreddit.

Moreover, the subreddit moderators are convinced their policy is needed to limit manipulation of popular sentiment, which they suspect is an ongoing practice on the webpage.

The pseudonymous “BashCo” is one of r/Bitcoin's moderators. To test this hypothesis, he did a multi-week data-analysis on the subreddit. Now, BashCo believes the results suggest what he had long suspected: the subreddit has fallen victim to extensive - and possibly automated - vote manipulation.

BashCo, who preferred to remain pseudonymous, shared his results with Bitcoin Magazine.

The Reliability

Collecting reliable data on Reddit vote manipulation is not as easy as it may sound – not even for subreddit moderators.

That's in part because Reddit itself seeks to tackle vote manipulation in several ways – but it’s unclear exactly how. While these measures (presumably) make it harder to cheat the system, and might help the sitewide Reddit administrators catch cheaters, it actually makes structural analysis for everyone else significantly more difficult.

“I don't know the full extent of Reddit's methods to obscure vote scores,” BashCo explained. “The Reddit administrators keep these mechanisms closely guarded, and it's likely an evolving system. That said, I do suspect that some vote cheating slips past them, just like how spam filters don't catch all spam. We've seen Sybil attacks on the Bitcoin network, and it's not unreasonable to assume that the same sort of thing occurs on social media. Bitcoin communities are unique targets for vote cheating due to potential financial incentives behind influencing public opinion.”

One method Reddit employs to battle manipulation – “vote fuzzing” – slightly randomizes all vote scores. This makes it difficult for outsiders to keep track of all votes on a specific comment. However, visual analysis (in other words: hitting refresh after a new comment to see if the score changed) suggests vote fuzzing occurs only after a comment has received a first real vote.

So BashCo wrote a basic script that keeps track of the very first vote on any comment received; the vote that shouldn't be influenced by vote fuzzing. More specifically, BashCo's script registers how fast a comment receives its first vote, and whether that is an upvote or a downvote.

BashCo ran his script on r/Bitcoin as well as several other popular subreddits for several weeks. And he claims to have found interesting trends. 

For one, there was a clear difference in the speed of voting on the Bitcoin subreddit, compared to all other subreddits he tested. According to BashCo, comments on typical subreddits took several minutes on average to receive an initial vote, while on r/Bitcoin a high number of votes were cast within the first minute after appearing online, and often even faster.

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BashCo believes the abnormal speed of voting suggests (though, doesn't conclusively prove) something out of the ordinary is happening on r/Bitcoin.

Note: Unfortunately BashCo has not (yet) graphed the timing on votes on other subreddits. He is currently re-doing this part of his analysis, and this article will be updated once this data is available.

The Data

Assuming the unusual speed of the initial votes indeed reveal some sort of manipulation might be going on, it’s interesting to see how these quick votes are cast.

Perhaps unsurprisingly, BashCo's data suggests they are politically motivated.

The moderator's analysis shows a very clear divide between users in favor of a fast block size limit increase hard fork, and those that are more conservative. Specifically, several of the most vocal supporters of a such a hard fork receive upvotes almost instantaneously, while dozens of opponents receive quick downvotes.

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If there is indeed any vote manipulation going on, BashCo's data suggests it's done to promote a hard fork block size limit increase. (But note that this manipulation might in that case be done by completely different users than those receiving the votes; they are not necessarily to blame for anything.)

Commenting on the results, BashCo said:

“The evident divide is certainly the most alarming aspect. I think if this wasn't politically motivated, then there wouldn't be such a clear delineation between each political faction. Instead, we would see more users from each faction receiving a mixed number of votes. Dozens of 'pro-consensus' users receiving instantaneous downvotes across hundreds of comments indicate that these are not organic voting patterns.”

The Conclusion

Of course, the available data is limited, and not necessarily conclusive. As always with this type of analysis, it's possible there are alternative explanations for the trends, and even coincidence cannot be completely ruled out.

But at the same time, the little available data might very well be the tip of the iceberg. Since the trend as shown by BashCo is clear, even with this little available data, perhaps a much bigger wave of manipulation is taking place on the subreddit – much of which remains undetectable.

BashCo himself, however, refrained from drawing hard conclusions.

“The data suggests that something is amiss regarding vote patterns. It does not outright prove vote manipulation is occurring, and we need to defer to Reddit's sitewide administrators for that, since they have a more complete picture. To date, Reddit administrators did confirm that multiple accounts are targeting users listed in the published data. This is certainly a piece of the puzzle, but it's a puzzle we can't solve to our satisfaction,” BashCo said.

Furthermore, even assuming manipulation, the r/Bitcoin moderator pointed out there is no way of knowing who’s behind it.

“There's many flavors of disruptive actors, and not all of them are malicious against the Bitcoin project,” BashCo said. “People have vastly different expectations for the project's future. People tend to become disruptive when their expectations aren't being met, regardless of how realistic their expectations were to begin with. They could be demanding something that's ultimately harmful to Bitcoin, but they still believe they have good intentions. The only way I know to correct this is for people to be willing to learn more about these complex issues from people with more realistic expectations.”

The Moderation

Moving forward, BashCo indicated that combating manipulation will remain top priority for the r/Bitcoin moderation team, though he believes it's an uphill battle. In potentially anonymous environments like Reddit, it's near-impossible to counter all attempts at manipulation, he thinks.


“Reddit is intended to be driven by user participation. Communities are expected to curate content via upvotes and downvotes. But some people place more trust in the voting system than I believe is warranted. While I'm confident Reddit is doing its best to combat manipulation, I believe it’s not at all uncommon. When we combine proprietary anti-vote cheating measures with potential Sybil attacks, it's impossible to say that vote scores mean anything without having much deeper insight.”

And perhaps unsurprisingly, BashCo and the other r/Bitcoin moderators have no plans to radically change the current moderation policy – though they have eased their guard a bit recently.

“Increased moderation is intended to prevent disruptive actors from inciting drama intended to take the focus away from Bitcoin,” BashCo explained. “Non-consensus clients like Bitcoin Classic and Bitcoin Unlimited are discussed frequently, and we encourage users to promote their favorite BIPs. But promoting non-consensus clients on r/Bitcoin is still off-limits.” 

Bitcoin Magazine has not been able to verify BashCo's data, but he did make his script publicly available. Since completion of this article, BashCo also shared his findings on r/Bitcoin.