The four really big prizes of the internet are: content, payments, discovery, and identity. If you think of each you no doubt also realise who the major players are and how the battle lines are drawing up. Amazon, Facebook, Google, SalesForce, Apple, Twitter, Ebay.

There is a lot of activity in the payments space, particularly around mobile. But identity, particularly authentication and the social graph, are seeing a blitzkrieg of activity recently.

Social media authentication is now commonplace across the web. Facebook Connect, for example, embeds Facebook functionality into millions of third party sites, applications and gaming systems (as does Twitter) enabling users to log in using their Facebook identity, connect with friends, and seamlessly post updates to their profile.

The launch of Google+ sign-in this quarter similarly enables users to sign-in to apps and sites via Google+, enabling the creation of an enhanced experience using the social graph and smart application of data.

Using the sign-in enables brands to access a whole range of information via the Google API including a user’s name, profile picture, Google+ ID, age range, language, people in their Circles, and any other information specifically requested by the app, and can even combine it with other Google APIs to enable access to additional Google services (Gmail, Calendar, YouTube etc.), though this will require a separate consent dialogue box.

This quarter’s Google I/O event featured a whole series of announcements of new features for Google+ which served to illustrate Google’s commitment to the bigger picture: making Google+ a layer over all other Google services.

It is wrong to think of Google+ as a social network. It is, as analyst Benedict Evans described it a “unified Google identity to tie all of your search and indeed internet use together”.

This quarter Instagram launched its “Photos of You” tagging feature which effectively carries Facebook’s people photo tagging feature through into the photo sharing service.

Meanwhile Amazon has also just launched an API for iOS, Android and the web, so that other site owners can allow their customers to log into services using their Amazon account, reducing sign-in friction.

With over 200m active Amazon accounts and a potentially seamless link to Amazon services this is yet another significant play in the battle for digital identity.

Why does this matter?

Clearly, for the big internet players, customer data is a vitally important strategic asset to enhance the experiences they can offer to drive adoption, usage and loyalty around their services which are spread over ever-widening ecosystems.

But there is also a huge opportunity for us marketers to plug into this data opportunity. We can capture more data through frictionless social log-ins; we can access data we do not have ourselves on our customers; we can access new data points, to power social CRM for example; we can blend and append data across channels to get a much better picture of a customer.

But we need to tread carefully. Who really owns this data? What are customer expectations around permission, privacy and configuration as the lines become grey across the ecosystems?

Which logins should we add to the interfaces we are trying to simplify for our customers – once there was just Twitter and Facebook, now come Google+, Amazon and others?

As ever, the easy, but correct, answer is probably to continue to focus on doing the basics better whilst at the same time experimenting with these new possibilities to see what works best for your business and customers.