A nonprofit is certainly possible, but it requires a
fair amount of effort to establish and to maintain. You would need to:
1. Establish the corporation with an educational purpose and containing other provisions required by Internal Revenue Code 501(c)(3). This is generally the easy
part. However, you might need to sever the "for profit" coin business from the "nonprofit"
Forum, Wiki etc to make this
work. Frankly. that may not benefit your ongoing business.
2. Apply to the IRS for 501(c)(3) tax-exempt status. This is a lengthy process with a heavy application package.
3. Corporate maintenance: you need to file annual reports, tax returns (even nonprofits file annual tax documents) etc. to maintain the corporate entity and the tax exempt status.
4. Officers and Directors: A corporation requires officers and directors. These positions would be easy to fill while your family is in the picture. If your family wants out of the organization, then a steady stream of volunteers would be required. Treasurer would have to maintain books and records, make payments and coordinate tax filings etc. I see this maintenance of a cadre of volunteers as the largest, long term obstacle.
Another possibility might be a trust, funded by life insurance, to maintain the non-business portions of the site. This may be simpler, as you'd only need a trustee to manage things.