People give to charity because they believe in a cause or an organization and they believe that in some way it will make them or the world better off. Parents give to Stanford University because they hope that a gift will give their child a better chance of being accepted.
Whatever the primary reason for giving, another compelling reason is to get a tax deduction. I don’t think people donate simply for the deduction, because by itself a deduction doesn’t increase your personal wealth. You can never make money, legally, by receiving a charitable tax break.
Any organization that promises to make you wealthy with a donation is a scam. If you do receive a benefit with your contribution, such as merchandise or services, you can only legally deduct the amount of your donation that exceeds the fair market value of any benefit you received.
If you make a donation, your decision is reinforced by the promise of at least saving some money on your taxes. Therefore, you want to make sure your donation is going to a IRS qualified taxable organization. You can find out whether the donation is qualified by checking IRS Publication 78, Cumulative List of Organizations.
Recently over 275,000 organizations lost their tax-exempt status because they didn’t file the proper reports. Many of organizations probably aren’t aware that they are no longer tax-exempt, so, particularly in the case of small organizations, I wouldn’t rely on their assurances that they’re tax-exempt. Check Publication 78.