NI0U,
You may already be aware of this since you've founded one.... but others may not.
The benefit of being a member of a 501c3 organization is that donations are tax-exempt: both for the donor as well as for the club (donor gets a variable tax break depending on tax situation while the club pays no taxes on the revenue). The IRS requires that an applicant be an established non-profit corporation in a given state before considering the IRS exemption under the 501c3 tax code provisions. Then, many states require another exemption in order to "publicly solicit" donations vs. Board members giving or over the transom donations. These vary by state and there are annual revenue thresholds whereby there is no reporting needed or there is some reporting or a lot of reporting. Regardless, a Form 990 must be submitted to the IRS annually to maintain the 501c3 recognition in good standing. These forms are available online for review (e.g., the ARRL's is online, etc.).
Does this help answer the Q or have I misinterpreted the head-scratching?
Frank
K4FMH