Whilst companies like Workday and Jive Software pioneered the friendly UI's that mimicked popular consumer apps for the work-place, surely nobody is better placed to launch an enterprise social collaboration tool than Facebook themselves.
In a move that mirrors Microsoft's acquisition of LinkedIn, but in the opposite direction (if that makes any sense), FB is moving into the enterprise space whereas MSFT bought its way into the social arena.
Of course, this is already a crowded area with big players such as Microsoft, again, with Yammer and Salesforce, to mention just a couple. Only time will tell if this is a wise move.
Google, for one, has learnt that it's not 'a given' when launching products in areas dominated by more specialised competitors. The biggest example being their crack at social with Google Plus, whilst 'Allo' - their messaging app - has not had the most auspicious start either...
Facebook At Work is launching next month