SourceForge recently instituted a donation system for projects and users, whereby you can donate some money to a PayPal account to show your appreciation for the free and open source projects you use. Donations to projects require opt-in from all the project's admins.
Jeremy and I have both opted-in to the donation system for the GNU Mailman project. I have set the donations email address to the Python Software Foundation's PayPal account. This needn't be set in stone, but we had to pick an address to turn this on and the PSF seemed like a reasonable choice. Note that the Python project is accepting donations for the PSF as well.
GNU Mailman remains free, in both the monetary and liberty senses of the word. I personally feel that the good will, help to others, insights, patches, bug fixes, and general good community that you already donate is enough reward. If you feel like making a monetary contribution as well, please know that the PSF is a US public charity under section 501(c)(3) of the IRS code. See
If you have comments or feedback about our choice for the recipient of donations, or about whether we should be taking donations at all, please email me directly.
Cheers, and happy holidays, -Barry