I answer questions both on serverfault & stackoverflow, although my user ranking is much higher on serverfault.com.
If i sign up for careers.stackoverflow.com as a SQL Server DBA, will this be worthwhile? or will i have to fork out more money for careers.serverfault to associate my sf user account if/when that happens?

Maybe being a SQL Server DBA is one of these gray areas in IT that is a bit cross functional where some questions are relevant for me on both sites, so I'm the gap case.