Allow users to "Show funding interest" in listed properties

[anaspk]

Here is a description of desired feature from client:

When a property is listed, the objective is that people reviewing the listing, can
indicate that they are interested in an investment in that property.

There should be a place somewhere on the property listing to add a check mark
or click to to indicate the interest. Once, they click or mark, then, display their
registration information that we should already have, give them the opportunity to
update anything, then ask them to agree to share that information with Project
Property Developer. Then email to the project property developer that an investor
has indicated interest in their listed property.

When Project Develop logs on to his/her account, they can see the listed property
and anyone who has shown interest in the property.

The person interested in the property would be a registered user, even as a guest,
to indicate the interest.

[anaspk]

Also ... allow interested persons to mention the number of "Investment Units" that they are willing to invest. And when displaying properties at various places, use this additional information to compute a figure for "Amount Invested" and show it alongside the property.