Monday, July 11, 2011

Google and suggesting friends

A timely paper out of Google at the recent ICML 2011 conference, "Suggesting (More) Friends Using the Implicit Social Graph" (PDF), not only describes the technology behind GMail's fun "Don't forget Bob!" and "Got the right Bob?" features, but also may be part of the friend suggestions in Google+ Circles.

An excerpt from the paper:
We use the implicit social graph to identify clusters of contacts who form groups that are meaningful and useful to each user.

The Google Mail implicit social graph is composed of billions of distinct nodes, where each node is an email address. Edges are formed by the sending and receiving of email messages ... A message sent from a user to a group of several contacts ... [is] a single edge ... [of] a directed hypergraph. We call the hypergraph composed of all the edges leading into or out of a single user node that user's egocentric network.

The weight of an edge is determined by the recency and frequency of email interactions .... Interactions that the user initiates are [considered] more significant .... We are actively working on incorporating other signals of importance, such as the percentage of emails from a contact that the user chooses to read.

"Don't forget Bob" ... [suggests] recipients that the user may wish to add to the email .... The results ... are very good - the ratio between the number of accepted suggestions and the number of times a suggestion was shown is above 0.8. Moreover, this precision comes at a good coverage ... more than half of email messages.

"Got the wrong Bob" ... [detects] inclusion of contacts in a message who are unlikely to be related to the other recipients .... Almost 70% of the time [it is shown] ... users accept both suggestions, deleting the wrong Bob and adding the correct one.
I like the idea of using e-mail, mobile, and messaging contacts as an implicit social network. One problem has always been that the implicit social network can be noisy in embarrassing ways. As this paper discusses, using it only for suggesting friends is forgiving and low-risk while still being quite helpful. Another possible application might be to make it easier to share content with people who might be interested.

For more on what Google does with how you use e-mail to make useful features, you might also be interested in another Google paper, "The Learning Behind Gmail Priority Inbox" (PDF).

For more on implicit social networks using e-mail contacts, please see my 2008 post, "E-mail as the social network".


Michael McDaniel said...

It's interesting to note that they don't show you who is already on Google+ and who is not. They don't tell you they're going to spam people who aren't on there already.

When I first saw it, I thought all those people were already on google+. And I was surprised. I didn't get fully wise until it recommended my MOM. :)

Matthias said...

Michael, Google+ will only send emails to non-G+ users with your explicit consent. You can include such users in your circles (which does not generate any mails by itself); they are clearly labeled with a little envelope. Once you try to share something with that circle you can _optionally_ check to "also email users not yet using G+". If you don't, only G+ users will receive your content.

(I work for Google).

Anonymous said...

The TOS do say that G+ contacts will be used in contact recommendations. Clearly this can disclose unwanted information (like the buzz launch did), though with plausible deniability in most cases.