Last year, Twitter decided that it needed consumer marketing support and hired a PR agency. The move came as a surprise, because in registering 500 million users it might have appeared that Twitter was not exactly struggling to attract attention.

Yet Twitter is just the most visible example of a trend that has taken hold across the digital spectrum. In recent months LinkedIn and Foursquare have also called in new consumer PR counsel, joining other emerging technology players such as Groupon and Airbnb, which have also established agency relationships.

These moves, say industry observers, reflect how companies like Twitter and LinkedIn are attempting to make their mark on mainstream culture. Garnering tech plaudits, after all, has become relatively easy; the bigger challenge comes in explaining exactly why your service is so important to Main Street moms, rather than Silicon Valley wags.

To do that, companies are hiring firms with strong consumer marketing credentials. Twitter appointed Edelman, albeit for a short-lived stint that did not exactly end as anticipated. LinkedIn and Foursquare, both of which declined to comment on this analysis, recently selected New York firms Maloney & Fox and M Booth, respectively.

“Many brands may not understand how to use consumer-focused PR to their advantage,” says M Booth CEO Margi Booth, whose firm also works for OpenTable and Rent.com.

There is something ironic about sophisticated social media players turning to classic PR advice. “They still need to be in the New York Times,” points out Edelman digital MD Marshall Manson. “If you’re an up and coming social network, you don’t need a tremendous amount of help building a community. What you need help with is how do we get on USA Today, or how do we get on Oprah. It’s classic PR.”

Foursquare, for example, recently used a focused PR blitz to showcase its integration with American Express. It is “lifestyle” efforts like these, says M Booth VP Brad Laney, that demonstrate the type of campaigns which companies in this sector should be creating, rather than focusing too narrowly on product publicity.

“There is a recognition that they can benefit from connecting with their consumers in this way and move the brand more mainstream,” says Laney. “It is about helping them showcase the role the brand plays in the everyday lives of consumers.”

Each of these companies, unsurprisingly, has differing PR needs. One thing that binds them, though, is that perennial public relations challenge: Proving their worth to individual users in an increasingly cluttered marketplace.

Some see this as a quintessential engagement issue, bearing in mind the spectre of Facebook, which hangs heavy over the entire sector. Facebook has gazillions of users, but its ability to make people use the site - and its many services - for long hours is one factor that separates it from the pack. One tech PR specialist that the Holmes Report spoke to for this story noted that newer social networks are simply trying to emulate Facebook’s success in this regard.

Others are less convinced by this argument. “They all think they are trying to do what Facebook has done,” says one agency source with numerous clients in the sector, who instead frames the issue as one of “reconsideration”. Sites like Twitter and LinkedIn boast hundreds of millions of members; the difficulty lies in persuading many of these people to reappraise their largely indifferent relationships with them.

At Twitter, for example, a crucial objective of its PR outreach was to make it more relevant to individuals. The brand has wider awareness than most social networks, but many users - say observers - still struggle to understand the exact benefits it might bring them. A “vertical marketing” strategy becomes particularly important here, as a way of connecting with specific interests such as sports, music or food.

“Once people have given you a try, how do you get them to come back?” asks Manson. “The next move is to get people excited about the platform again.”

Making that case to the clients in question, say some observers, is not always straightforward. “Sometimes whey they ask for consumer PR, they are really thinking about broader tech or corporate,” points out the agency source. “Part of this is education about what is the most effective way to talk to consumer media. It‘s not like a tech publication where there is a built-in interest in covering them.”

That factor cuts both ways, given that mainstream consumer titles are often less tech-savvy than you might anticipate. “It’s not as easy as calling up and pitching a Dyson vacuum story, or a story about mascara,” notes the agency source. “It takes some time.”

Time is not something that all of these companies have a surplus of. Not all of them have fully-formed business models, and, whether publicly- or privately-owned, they all have investors that expect increasing levels of growth. “You’re going to have to give new or refreshed use cases or brand propositions to users if they are going to give you a second look,” points out Manson. “The PR/marketing push is as much about satisfying advertising as about gaining users.”

Not that, by all accounts, there is that much money in these programmes for established consumer PR firms. “Do they invest enough?” asks the agency source. “No, but they will. A lot of firms are willing to take them on because they are the prestige brands of the moment. That will change - it will have to as they figure out their marketing strategy.”

That strategy will also, increasingly, need to be about more than just publicity. The last two weeks have seen concerns surge over Google’s new privacy policy, indicating areas where people still require considerable reassurance. “Trust and safety are big issues, and you’re already seeing that with Google and Facebook,” says Laney. “They need to communicate proactively and underscore the measures in place that safeguard consumers while reminding them of all the positive attributes that attracted them in the first place.”