I own a small business so I'll chime in on this. In general, SSN's are provided to parties where it will stay hidden (banks, credit cards, etc). EIN is more or less the number that the public sees. If you are applying for credit cards, I wouldn't worry about giving them your SSN as long as you follow best practices - don't send your SSN in the mail or over unsecured email/forms/etc.

When companies are requesting W9's to give you 1099's, its better to give then an EIN because companies other than banks/cc companies have a more lax way of handling W9's. That would be the only time I'm weary of giving a SSN.

You can get an EIN pretty easily, in fact you can create a sole proprietorship DBA yourself, and request an EIN instantly from the IRS site.

Aside from that, if you have enough credit cards and dont plan on opening anymore, you can request a freeze on your account... meaning people cannot access your credit report (hence instant denial for credit) unless you unlock it. IMO thats the best way to protect credit, instead of trying to undo indentity theft with the "monitoring services". You can buy identity theft insurance these days but why bother.