I treat these networks like I treat email. I have multiple email accounts and multiple social networks accounts. Find an email provider that provides filtering and forwarding.
Mine are roughly divided like this;
1) Personal, close, true and trusted friends and selected family members.
2) A business account for legitimate and legal uses. One for each business.
2) Social contacts, acquaintances, blogs, SOME social media sites.
3) Throw away accounts, may or may not use a pseudonym with significantly different demographics. This is used for sites that demand a valid email address. This account is rarely check except to hassle Nigerian scammers.
Use your imagination for other possible uses.