Google is wrestling with a thorny conundrum: should it block its own Chrome browser from its search index for between a month and a year for breaking its own rules on paid links, after a mixup by some bloggers for a video advertising scheme?

The problem has arisen after Google paid Unruly Media, an international media agency, to get a number of paid bloggers to promote a video for its Chrome browser featuring a US flour company.

Update: Google has demoted its Chrome browser in search results as a result of the scheme. Read the latest story.

But while the bloggers did the job they had been asked to, and put up the video, some went beyond what Unruly Media – and Google – had expected them to, and included links to places where you could download the Chrome browser. Crucially, though, they didn't use the "nofollow" text that Google mandates for paid links. That, strictly, took them over the line on paid links.

Update: a company called Essence Digital has now said that it acted as an intermediary between Google and Unruly Media. In a post on Google+, it said:

We want to be perfectly clear here: Google never approved a sponsored-post campaign. They only agreed to buy online video ads. Google have consistently avoided paid postings to promote their products, because in their view these kind of promotions are not transparent or in the best interests of users.

In this case, Google were subjected to this activity through media that encouraged bloggers to create what appeared to be paid posts, were often of poor quality and out of line with Google standards. We apologize to Google who clearly didn't authorize this.

The "sponsored" blogposts (such as this one, though it does not link to Chrome) were first noticed by Aaron Wall at SEO Book. He commented: "You can say they didn't require the links, that the links were incidental, that leaving nofollow off was an accident, etc ... but does Google presume the same level of innocence when torching webmasters? They certainly did not to the bloggers who reviewed K-Mart [who were removed from the search ranking] and the Google reconsideration request form states: 'In general, sites that directly profit from traffic (e.g. search engine optimisers, affiliate programmes, etc) may need to provide more evidence of good faith before a site will be reconsidered.'"

At Search Engine Land, Danny Sullivan wrote: "Potentially, all this means that Google will have to ban the Google Chrome download page over paid links. That would suck for Google, since it's busy running ads for Google Chrome, which will in turn prompt people to search for it. Right now, the page appears at the top of results for searches on 'google chrome'."

Andrew Girdwood, who has worked in the past with Unruly Media, said: "My hunch is that individual bloggers have written editorials for their sponsored video (which is just a CPA [cost per action] ad [where bloggers would get paid any time somebody watches the ad] – like so many others, just like any affiliate deal) and put a link naturally into that text … I doubt these posts were about links."

Scott Button, the chief executive of Unruly Media, told the Guardian: "A blogger, who we didn't ask to link to a Google Chrome page, linked to a Google Chrome page, and did so without using the nofollow attribute. Obviously they shouldn't do this in the context of a blog post that embeds one of our sponsored videos. As soon as we found out about it, we got it fixed. To be clear, we're not in the business of getting bloggers to write about products or link to advertisers' websites. We distrubute branded video content, and we pay bloggers (and big websites and app developers) when their audiences watch the videos. That's what Google paid us to do, and that's our business. The SEM [search engine marketing] angle is basically a red herring - it doesn't bear any relation to our business nor any relation to the objectives of the Google Chrome campaign."

Button declined to say how much bloggers are paid per viewing. Unruly Media runs about a thousand social video campaigns annually from nine offices, Button said. "It's a grown up business and growing very fast, but this is still small beer in relation to the $500bn plus that brands spend on media each year."

But just as concerning for a number of observers was the content of the posts preceding the video: Wall called it "low-quality filler pablum content that the Panda update was alleged to discourage", while Sullivan commented: "That's perhaps the bigger problem with this campaign, much more disturbing to me. Google's paying to produce a lot of garbage."

But that "garbage" appeared to be having benefits, based on Sullivan's searching: the Telecommutingmommies post linked above ranked second, when he looked, in a search for "google chrome benefits". When the Guardian tried the same search on Tuesday evening, the same post also ranked second.

That, says Sullivan, pollutes the results: "Imagine you're someone trying to understand the benefits to using Google Chrome versus other browsers. Out of 21m possible matches, two of Google's sponsored garbage posts make it into the top 10 results."

Even worse, he says, is that the video which caused all the trouble doesn't actually mention Chrome at all. "You may have seen on television already. It has nothing to do even with how Chrome actually helped the Vermont flour producer featured, King Arthur Flour, succeed … Since King Arthur Flour has been online since at least December 2006, I'm willing to bet it got its start through the Internet Explorer browser. It sure wasn't Chrome, which didn't exist at the time."

In a statement, Google said: "Google never agreed to anything more than online ads. We have consistently avoided paid sponsorships, including paying bloggers to promote our products, because these kind of promotions are not transparent or in the best interests of users. We're now looking at what changes we need to make to ensure that this never happens again."

(Disclosure: Unruly Media provides the Guardian's Viral Video Chart)