Remember those Find Your Old Classmates ads around the time of the dot-com boom? The sites behind those ads, like, were really the first iteration of social networking sites. Back then, social networking was all about using the power of the internet to connect with people that you had lost touch with.

Fast forward to today and social networking is all about the sharing of content. But sharing content within a trusted circle. Part of Facebook’s success is because it started out a closed social network, only eligible to students at specific schools. LinkedIn has a huge emphasis on whether someone is connected through one of your trusted friends, colleagues, or acquaintances.

But is the social web now evolving from trusted sharing to open discovery?

Trusted sharing is extremely useful in finding great recommendations, but usually only for topics that you are interested in too, as chances are your social circles have more or less the same interests as you. For example, I know my social circle will deliver great and copious amounts of recommendations on good restaurants in London, but less so on which private jet to buy.

Enter something like Pinterest – which has seen tremendous success around its model of open discovery and cataloguing of photos. Users create public “pin boards”, where photos of the topic can be collected and curated. Sometimes you don’t know what you’re looking for until you find it – and while text-based search engines and text-based social networks are great for when you can describe what you want in words, Pinterest’s image-based cataloguing allows users to explore – and discover – things they didn’t even know existed. Anyone who has tried to find images around a topic in Google Images knows exactly the frustration that Pinterest solves elegantly.

For a newly launched start-up, what was surprising was the amount of home cooks and brides-to-be that were interested. Usually, it’s the male web geeks who are the early adopters – but for Pinterest, 70% of its early users are female.

And it’s not just new start-ups like Pinterest that are enjoying this shift from trusted sharing to open discovery. Remember Pandora and StumbleUpon? Both launched in 2007, saw some early success, but struggled to gain traction. But both have seen a revival in fortunes lately, especially StumbleUpon, doubling its visitors in the last few months after years of stagnant growth. Both are social discovery networks – Pandora lets you explore music based on your listening habits, and StumbleUpon recommends new stories based on your past reading habits. A new mobile app, News360, takes it one step further by analyzing your social media posts to find out your interests, and then delivers a customised news feed to you.

Even Google Plus is getting into open discovery, as apart from seeing things shared by your friends, you can also see public items shared geographically near you – helping you to discover your local neighbourhood.

What does this all mean for businesses trying to reach customers through social?

Firstly, don’t abandon your efforts in trying to build quality, trusted relationships with your customers. A huge part of your efforts should still be on Trusted Sharing, whether it’s building the brand to consumer relationship or positively influencing word-of-mouth trusted recommendations. But investing in the social discovery space can be especially powerful in situations where it’s more of a one-time purchase or where awareness of your brand or products are low among your target customers. Think bridesmaid dresses or designer furniture, where it would be hard to build that trusted relationship online beforehand.

Customers will use social discovery networks like Pinterest and Google Plus in the same way they go and browse in shops instead of buying through Amazon – sometimes they have a vague outline of what they want, but need that inspiration and discovery to truly define what they’re looking for.