What really irks potential donors about their contact with charities?

Marc A. Pitman, a fund-raising consultant, decided to use the popular social-networking site LinkedIn to pose that question to real-life donors.

At the top of the list for many donors: the freebies that are included in many direct-mail solicitations.

“Don’t send me junk in the mail like address labels, notepads, and pennies,” writes one donor. “I have an understanding of the costs of printing and mailing and including these items with a solicitation letter [and it] makes me wonder exactly how much of my donation will be used for the core mission.”

Other donors griped that charities had given their contact information to other organizations, so donors were overwhelmed with telemarketing calls and direct-mail appeals.

“Every nonprofit should thank their donors with no strings attached, no additional asks or invitations — just a pure thank you,” writes another.

Mr. Pitman says he plans to follow up on the responses on his blog, The Extreme Fundraising Blog.

Tell us what has frustrated you the most about charities — whether you work for one, volunteer, or offer support to a good cause.