DoNotFeedTroll/Sam Fentress
Digg, a site that tips articles of interest to possible readers, offers a look at one example of trolls taking over:

The general awfulness of YouTube comments is well-established, forever exceeding our expectations of what "rock bottom" could mean in terms of reasonable discourse. But if you've felt that popular videos — particularly those boosted by Reddit's nearly 6 million strong r/Videos community — have reached a fresh hell of trollerly as of late, you're absolutely correct.

Much of what follows is hard to understand because gentle readers have had many more useful things to do than follow new media fads.
But the gist seems to be that “the sharpest tip of a particularly ugly iceberg” is “Berta Lovejoy” (possibly a man and not a feminist), who has a talent for staying at the top of comments on YouTube peak videos. This is likely due to a loyal band that upvotes comments irrelevant to the vid. This comment to this vid (NOISE LEVEL CAUTION) of an earsplitter monster truck rally is cited in evidence:

It's pretty clear to me why Reddit upvoted this video, you can't hide the blatant hidden messages from me. The monster truck represents males, the cars represent females. Whilst the cars (females) outnumber males and are the more efficient, convenient, safer form of travel, the monster trucks (males) step over us for no apparent reason, halting progress in society. It makes me sick seeing videos with these hidden messages get upvoted by males who know EXACTLY what the true message behind the video is.

Only an upvote claque could think these remarks relevant to a monster truck rally, let alone make them the top comment.
Claque? Yes, and this behaviour is hardly new, it dates back to at least the 18th century, the age of white powdered wigs for men. By the 19th century, in France, elaborately organized groups of claques (clappers) were hired to promote new theatre works:

By 1830, the claque had become a regular institution. The manager of a theatre was perfectly able to send an order for any number of claqueurs. These people were usually under a chef de claque (leader of applause), whose duty it is to judge where their efforts are needed and to start the demonstration of approval. This takes several forms. Thus there are commissaires (policemen), those who learn the piece by heart, and call the attention of their neighbors to its good points between the acts. The rieurs (laughers) are those who laugh loudly at the jokes. The pleureurs (criers), generally women, feign tears, by holding their handkerchiefs to their eyes. The chatouilleurs (ticklers) keep the audience in a good humour, while the bisseurs (encore-ers) simply clap their hands and cry "Bis! Bis!" to secure encores.

On the other hand, claques were also used as a form of extortion, as singers were commonly contacted by the chef de claque before of his or her debut and was forced to pay a fee, in order not to get booed.

So most of the theatre was going on in the pit, not on the stage. That is typical of many popular blogs today, where the real action is in the combox, whose contents often far exceed the post in length and usually warrant much more supervision.
But sometimes the harm is more serious. Facebook trolls can potentially destroy reputations and careers other than their own, as Rachel Alexander, editor of Intellectual Conservative notes,

The conservative Citizens’ Post page on Facebook was hijacked by the “Goatz Alliance,” which also goes by the name “Busta Troll,” by pretending to be from a conservative organization called Freedom Alliance. The bullies also set up several fake conservative Facebook groups to give themselves credibility. Once they cajoled the owner into giving them admin privileges, the hijackers posted anti-conservative propaganda all over the page. On one of their fake Facebook pages, a cyber thug claims to be paid by George Soros.

Another conservative Facebook page, “America, the Next Generation,” was hijacked not just once but twice by the cyber thugs, who pretended to offer help fixing a rude post about Obama, but then posted goats. R.W. Burgin, who runs a Facebook page called The Seditionist, told The Examiner that liberal cyber thugs copied photos from his page and photoshopped them into parody pages and videos, including alongside pornography. He was called a pedophile and his employer was contacted, in order to try and get him fired.

Careers could be sidetracked simply because the offensive information remains on Google indefinitely, warning future employers to avoid the person, regardless of fact.
This is not happening only to conservatives. Consider the story I recounted here earlier, of how a restaurant was crippled and later closed, probably mainly by false information on Google maps, unbeknownst to the elderly proprietor.
Anyone who communicates on the Internet runs these risks. What some of us see as freedom to contact like-minded people in other parts of the world, others see as freedom to destroy people in ways that would not usually work in a small insular town (because everyone would know if something just plain wasn’t true).
I was tempted at first to think it all might be exaggerated. Until, that is, a Canadian blogger couple I know suddenly found that anyone who tried to reach their popular site (Blazing Cat Fur) faced this message from Google-owned Blogger:

Some readers of this blog have contacted Google because they believe that this blog's content is objectionable. In general, Google does not review nor do we endorse the content of this or any blog. For more information about our content policies, please visit the Blogger Terms of Service.

I UNDERSTAND AND I WISH TO CONTINUE/ I do not wish to continue

The main thing that distinguishes their blog from many is a willingness to discuss the growth of violent Islamism in Canada and the western world openly. That stance has been risky in Canada.
But now, will Blogger make a note of who chooses to travel through the warning and report back to the government later? Before you think that’s daft, read this. The couple have since moved to a private domain.
The Internet is a sea, and like most well-travelled seas, it gets infested by pirates. We are only beginning to figure out how to deal with that. See also: How to sink a competitor with Google Maps Here’s Troll “Free Insults” Joe, who reminds me of a cartoon creature who lived under a log in the Saturday funny papers. But he’s bigger and badder now, out of his log, and it will take some time to determine how to deal with him:
 

September 25, 2014 Denyse O’Leary is a Canadian journalist, author, and blogger.