Looking at many professional and personal presences on the internet it seems that there is a definite divide for people to have a specific presence for one or either but not both together. I mean Linkedin for Professional use , Facebook for personal use with up to two separate personae on twitter.

Has anyone successfully managed a professional presence on Facebook to capitalise on a growing presence of professional bodies reaching out for professional connections rather than personal connections.

For example if I was reaching professionally to companies/organisations on Linkedin and via a professional personae on twitter is it necessarily good to reach out using a professional persona rather than a personal persona on Facebook ?

What reason would companies/organisations use Facebook if they can reach out to professionals on Linkedin ?

I've spotted entries like a Led Zeppelin tribute band on Linkedin, which i can only assume is open to social rather than professional connections ?