In recent weeks I’ve written several times – with all good intentions – about the lack of engagement of many internal communication professionals in the Web 2.0 revolution. But laggards avoid the issue at their own risk. As a recent post in the Melcrum blog argues, the PR world is seeing its own version of global warming – the blurring and melting of firewalls between internal and external audiences. As technology becomes increasingly mobile and affordable and communication habits evolve, it’s becoming increasingly difficult (and irrelevant) to think of employees as an insular, distinctive audience separate from external stakeholders. We always knew there was considerable overlap, of course, since employees are also consumers and critics who have private lives outside the office. But the premise was that much of the company-employee communication process could still be neatly managed in-house. No longer. (For one thing, the primary reasons for trying to keep the internal communication private – to protect confidential information – is becoming less relevant in this age of transparency and consumer advocacy.) Companies that understand this trend are not only using Web 2.0 tools – wikis, idea management systems, blogs, peer networks – within the organization to foster dialogue with their employees, but also increasingly thinking about what external tools can be leveraged for internal benefit. They understand that limiting outreach to formal internal channels is accepting an increasingly limited share of voice among their employees. In this brave new world, the challenge for companies is to be a relevant part of important conversations that involve their employees…no matter where they occur.