How many social network sites is it sensible to use?

I'm on 4 Flickr, Myspace, Spidercircle and Facebook. I know some people who use loads, what's a sensible figure.

How many social network sites is it sensible to use?fake myspace

I'd say 3-5 depending who you are using them for. Four sounds like a good number to me.

I think it's good to separate work, play, old friends, and dates. Can you imagine your best friend from the 3rd grade finding you and then leaving an embarrassing message about poop and Mrs.Whatshername's coffee in a place where a potential lover could read it? Or what about an old friend saying something that contradicts what you told your coworker?

How many social network sites is it sensible to use?myspace pics myspace.com

Er, none for me. I just don't get along with them.