Is Facebook Usage Boosting LinkedIn Usage?

Funny, I've been a long time LinkedIn Member, almost 2 years now.  I've been a Facebooker for almost 6 months. For almost a year, my LinkedIn network has grown slowly, very slowly. But now, I'm noticing that there has been a wave of new LinkedIn contacts requesting to become part of my network. Not just friends, those stick to Facebook, but real colleagues who have jumped into the LinkedIn network.

Could it be that there is an increase in LinkedIn users as Facebook popularity grows? Both towers seem to be adding users, both for very different reasons.  I'm still of the belief that you don't want to mix business with pleasure, not with the permanence that the internet can bring to your profile and your reputation. I'm curious to know - is maintaining two indenties - for work and for play a common occurrence?  Or are folks starting to melt the two together? Alec Saunders suggests that Facebook will replace the social networking of LinkedIn. What say you?