Plus-one-ing (or however you write that!) a link doesn’t make it appear higher in search results–yet. The search result shows up in the same order it would have, annotated with information about people who have +1′ed it.

After seeing lots of confusion about this, we followed up with a Google spokeswoman this morning to talk through exactly how this works.

Eventually, the plan is to consider +1 votes as one of many signals in Google rankings, she said. But right now, while +1 activity is just getting started, Google is excluding it from its ranking algorithm. In part that’s because early +1 users could warp search results before there’s enough data.

Update: This topic seems to be confusing even at Google. Google just clarified via email that +1′s from people in users’ social circles will be included as a signal in their personalized results, but not overall search rankings.

Currently, Google does use Twitter shares to help rank core search results. That was part of its big social search launch in February.

So for the moment, sharing a link on Twitter counts for more in the Google search algorithm than +1′ing it on Google.

Though Google may not re-rank yet based on +1, people who sign up to participate in the trial will start seeing +1′s from their friends and the rest of +1 testers immediately.

So as not to crowd the page, if a link has been +1′ed more times than it has been shared on Twitter, the +1′s will show up, the spokeswoman said. If there have been more Twitter shares than +1′s, those will show up.

Google does not yet count public Facebook “likes” as a social search signal, though it plans to, Director of Product Management Mike Cassidy told NetworkEffect earlier this month. At the time, Cassidy maintained that the omission of Facebook data wasn’t due to tension between Google and Facebook over personal data sharing. Rather, he said, it was a “technical issue” that would be resolved soon.

The emphasis on identity aggregation is an interesting indicator of how Google approaches social as it rolls out further products on that front in the next few months.

Though I’d heard Director of Search Product Management Mike Cassidy describe Google’s approach to social search when the company started sprinkling it throughout search results last month, this particular angle was increasingly apparent at a panel on social signals in search where Cassidy spoke at the Search Marketing Expo in San Jose today.

“We actually do try to map one true person,” Cassidy said. “The more we can do to associate content to a person, the better,” he added, calling this “AuthorRank.”

Cassidy appeared with Microsoft’s Paul Yiu, principal group program manager for Bing Social. Both are currently conducting tests on social search within the U.S. that they said are going well and should expand elsewhere “soon.”

“We measure everything at Google, and the results are all we hoped for,” said Cassidy of click-throughs on the new social search features. Social, he said, is “a great signal and people are using and enjoying it.” (That’s in contrast to another search expert at Google who earlier this year called social “a tiny signal.”)

What would a social story be without some Google-Facebook awkwardness? Cassidy avoided mentioning Facebook even as he discussed aggregating the Web’s social signals. It turns out Google social search does not include Facebook data, even though its intent is to include all publicly crawlable social data. (Facebook fan pages do show up in normal Google search, but they are not given special social ranking.)

Cassidy maintained that the omission is not because of ongoing tension between the companies about personal data sharing. Rather, he said, it’s a “technical issue” that will be resolved soon.

Unlike Bing, which provides some social results (for instance, heavily tweeted links) for logged-out users, Google shows social search only for users who are logged in to its own network. Bing’s big social signal is Facebook, and it automatically detects Facebook users who are logged in. From what Yiu said, it sounds like Bing is trying to find authorities on certain topics on Twitter rather than analyze the social graph there, as Google does.

But Bing is also connecting the social dots between various versions of an entity. One interesting thing that Bing has started doing is associating a company’s latest official tweet with its name. So, for instance, if you search for Netflix on Bing right now, you’ll see a tweet from yesterday about Mardi Gras as part of the top entry about the company.

Also, though search engines are usually reticent to disclose specific factors in their algorithm, Liu said Bing has found a high correlation between quality tweets and tweets that contain links.

What Google is doing today is making some careful tweaks to weave social signals into search: Most notably, bringing social search results up from the bottom of the page and parsing links shared by friends.

Google has tried to bring in new blood to help it “get social,” most prominently hiring the PayPal and Slide founder Max Levchin by acquiring Slide. Today’s social search launch was put together by another serial entrepreneur who came into the company through an acquisition: Mike Cassidy. His last company, an online travel guide called Ruba, was sold to Google last May.

Cassidy was a significant get for Google, though he’s stayed under the radar till now. Prior to Ruba, Cassidy had founded and sold three previous companies: Xfire, Direct Hit and Stylus Innovation.

While his title at Google–product management director for search–doesn’t have the word “social” in it, Cassidy noted in a phone interview on Wednesday that Ruba was a social company; it was specifically focused on recommendations by friends. In fact, he said, an early name for Ruba, which was backed by Benchmark Capital and Draper Fisher Jurvetson, was “Friendstips.”

Back to Thursday’s launch: Google already has a “social search” product that turns up for a minority of queries in the No. 9 and 10 spots at the bottom of its results page for logged-in users who have connected their Google accounts to social services like Twitter.

Now those results will show up scattered throughout regular results. But that’s only for users who are logged in, and only when a social result is deemed relevant.

The other big change is Google will also now give higher ranking to URLs that are shared as links by friends on public sites like Twitter and Quora. Google will try to determine on a per-user and per-tweet basis if a link is relevant to a certain searcher based on which users shared it.

So, for instance, if an article was shared by a person you are friends with on multiple services, Google will think it’s probably more important to you. Or if a video has been shared by a lot of people, including your friends, there’s a good chance it will turn up high in your results on that topic.

Lastly, Google is tidying up some stuff so users can link social services to their Google accounts without displaying them for all to see on their public Google profiles.

Google’s search folks are not necessarily in alignment about the importance of social. Cassidy said Wednesday, “Recommendations from friends are some of the most powerful recommendations in the world. We’re trying to turbopower that. Google’s mission is organizing the world’s information, and this is an extension of that.”

But one of Google’s search scientists was recently quoted pooh-poohing the potential for social to change search. “Social is just one signal. It’s a tiny signal,” Amit Singhal told Bloomberg BusinessWeek.

Here’s a side-by-side comparison from Search Engine Land about what social signals Bing and Google used as of December. Since then, Bing has upped its special integration with Facebook to include pages “liked” by searchers’ friends.