First partnership that could get us half a million users - help!

We are a startup currently building a prototype version of a software with 20 developers within the websemantics field. We are developing a really innovative tool and have already received the attention of the biggest player on our market in order to collaborate.

Our potential partner has a community of:

• 465,000 registered users,
• over 35,000 companies to their database,
• 2,000 paying subscribers (which in my opinion could be better since people can find

  their premium data on google...so the incentive to pay is reduced).

As part of our partnership, I am hoping to get access to their customers' base so that we could quickly get traction to our webapplication and lift our startup of the ground quickly.

The content of the partnership agreement (it will be formally put in a contract) is:

• They provide us key aggregated data that only them can provide right now
• We provide our new technology to automatize cleansing of data, provide statistics,
  and visualisations tools (which would not be possible without our technology)
• The common output is the creation of a website showing statistics to end-users on
  the market (those statistics are not available yet on the market since they require
  a lot of efforts to harvest).
• Both parties want to redirect the end-users to its own premium data.

Therefore, I have identified the following scenarios to structure the partnership:

1. We have a mutual branded website and split revenues
2. We have a mutual branded website redirecting to each others premium data
3. We let them be the face of the website, we provide our tools to help them and in
   return we get authorization to contact their users to redirect them later on to our
   own website.
4. We let them be the face of the website, but they allow us to push our premium
   services on it? This mean we need to have enough possibilities to be visible

Hence my questions are:

• Which scenario would you recommend and why? Personally I tend for number 1 and the
  partner would go for 2 most probably.
• What is the best way to secure acquisition of their users' community (they allow us to
  do so)

Any other advice is welcome.

Here's the breakdown:

1. Option 1 is the most fair to both parties.
2. Option 2 is a nightmare of blame waiting to happen.
3. Option 3 is unbalanced in favor of your company.
4. Option 4 is unbalanced in favor of their company

If you can get away with it, go for option 3. Licence your tools to this company for a fee plus allowing you to contact their customers. In the meantime you will be developing the next version of your tools and later launch your own branded website with this customer base to draw on.

I don't see the other company going for this though. It's very risky for them in the long term.

Option 1 on the other hand is mutually beneficial, without anybody feeling like one side is getting more out of the deal than the other. A true win-win situation.

Option 2 is bound to end in a fight. There's just too much ambiguity when it comes to offering an unequal 'tit for tat' option. This option also detracts from unity. The finished partnership should look like it's coming from a unified place to the end-user.

Option 4 sells you short. You have something that is worth a lot to this company and you shouldn't merely be given the opportunity to advertise to the customers of the new site, but should share the revenue.