I agree completely with Rod. If the customer is not a big part of your overall receivable, then the only other possible consideration is do they have the potential to become a big part? Will they overcome their current cash flow difficulties? If your gut instincts tell you the answer to both of those questions is no, then prepayment is the way to go. Even if they don't have cash flow issues but their accounts payables department is managed poorly, that's still an issue you may want to stay away from.

For B2B listings, my vote would be for Netprospex.

As a business owner, I face similar issues myself. I'm sure you already know this but for something like this, you really should consult a lawyer and a tax professional. Having said that, the cleanest and safest way to do this would be to dissolve the current S-Corp and create a new one under a different name. This way there isn't any controversy over ownership. Hopefully you have a partnership agreement that covers the dissolution of your company. If not, you'll need one now. If you incorporate your own S corp in CA, you will have to register in IL as a foreign corporation. If you won't have a physical presence in IL, you will need a registered agent.

I have found networking events to be the most effective way to meet influential people who may be able to help you in your career. I have found job fairs to be a waste of time. My suggestion is to find out events that Facebook is hosting. Try to find out who from Facebook will be attending. Do some research on those attendees. If you get a chance to meet them at the event, do no talk about yourself. Talk about Facebook and the specific Facebook employee you're talking to. Let them know that you follow Facebook. Be genuine and personable. Wait until they ask you about yourself. Remember to bring a business card. (One with a photo would be a really nice touch so they can remember your name and face.) If they give you their business card, send a simple "it was nice to meet you at" email. Don't immediately ask to connect on LinkedIn. I personally hate that. If you made a positive impression, chances are they won't mind engaging with you. Cultivate the relationship. That's how they get to know you and keep you top of mind for opportunities.

I recommend checking out Netprospex from Dun & Bradstreet. It is was I use and I found it to be reliable. You should know it is expensive. Data.com from Salesforce is Ok too. If it's in your budget, check out what kind of information they have and see if it meets your needs. If you can't find a service that collects the information you need, then you have to collect it on your own. This will be more expensive and time consuming. You will have to create a network of sites that host content that your potential audience would be willing to trade their information for.

You can simply divide equally among the three companies or divide the fee based on usage. Count the volume of mail received for each company. Each individual company's share would be Individual Company divided by the Total.