Update: Search Engine Roundtable says there was no update on the date Enge points to.

While we certainly don’t know for sure, there are signs that Google could be turning up the dial on just how impactful mobile-friendliness is as a ranking signal for websites.

Do you think it should be a greater signal for ranking? Let us know in the comments.

As you’ll recall, Google launched an update in April, which it had announced months earlier, that was aimed at giving sites that are mobile-friendly (and pass Google’s mobile-friendly test) a boost in search rankings. It was still meant to only be one of many signals Google uses, but a signal nonetheless. Prior to its launch, the update became synonymous with “Mobilegeddon” as webmasters and SEOs braced for a big shake-up in search results.

Early reports after the launch however suggested that the impact may not have been so great after all. Even Google’s own Gary Illyes suggested that the number of sites may have been lower since so many sites became mobile friendly in anticipation of the update.

One study we recently looked at came from Stone Temple Consulting, who has been doing some great research into how Google works (see our coverage of their studies on Google’s indexing of tweets).

According to that, nearly half (46%) of non-mobile-friendly URLs that held top 10 spots on April 17 lost ranking, while fewer than 20% gained. Other findings included:

– For URLs that dropped in ranking, the drop for non-friendly URLs was more pronounced – an average of 2 spots – than for mobile-friendly URLs – average of .25 spots.

– Overall, the study found a 1.3% increase in mobile-friendly URLs in search results. While this does not approach the impact of Panda or Penguin algorithm updates, this is the first such change by Google, and we expect more changes and an increased impact over time favoring mobile-friendly sites.

Stone Temple’s Eric Enge concluded in the report, “In summary, I’d suggest that the impact of this release was indeed significantly bigger than originally met the eye. The trade press did not see it as large because of the slow roll out, and the intervening Search Quality Update. In addition, this is likely just the start of what Google plans to do with this algorithm. It is typical for Google to test some things and see how they work. Once they have tuned it, and gain confidence on how the algo works on the entire web as a data set, they can turn up the volume and make the impact significantly higher. It’s my expectation that they will do that. In the long run, don’t be surprised if the impact of this algorithm becomes even greater, and that people will stop debating whether or not it was greater than Panda or Penguin.”

Enge shared some additional analysis related to the update on Google+ today. He believes he has found a sign that Google may be giving the mobile friendly signal more weight now. Here’s the post:

It wouldn’t be much of a surprise to see Google giving the signal more weight. They did make a pretty big deal about it ahead of the launch, and gave webmasters and SEOs a great deal of notice in advance. Google has also been talking about how mobile search volumes are overtaking desktop in a number of countries. As that gap continues to widen in favor of mobile, it only makes sense that Google utilize this signal more.

In related news, Adobe released its Digital Advertising Report for Q2. While it’s only a small section of the broader report, it does look at the impact of Google’s mobile-friendly update. According to that, organic traffic was up to 10% lower among sites with low mobile engagement.

“While there wasn’t a precipitous drop among non-friendly sites, the effect is pronounced over the 10 weeks after the event,” said Tamara Gaffney, principal at Adobe Digital Index. “Such continued loss of traffic suggests that immediate emphasis would have been placed on paid search as a quick way to recover traffic. But that strategy is not necessarily sustainable.”

“Brands that neglected to address their mobile Web strategies are seeing mobile advertising via Google’s network delivering less value at a greater cost, with a growing gap between mobile click-through rates (CTRs) and cost-per-clicks (CPCs),” Adobe says. “ADI reports mobile CPCs are up 16%, while CTRs are falling, down 9%.”

“Increases in CPC stretch marketing budgets due to what is known as click inflation–advertisers have to spend more just to stay even,” added Adobe Digital Index analyst Joe Martin.

You can read more on the report’s findings, including why Adobe says Google is “losing ground as a marketing vehicle” here. The full report is here.

Should Google crank up the dial on the mobile-friendly signal? Have you noticed anything on your end to suggest that they’ve done so? Let us know in the comments.