Donation can be done at donate.limesurvey.org.
By your donation you are giving this software a future - so we can keep on creating new features and versions.
If you are a registered user (registration is free) you will be marked for one year in the forums as donator and so other members will see that you are a supporter of the LimeSurvey project. This also motivates our team members to support you with higher priority.Although you can donate without registering on LimeSurvey.org we strongly advise to register an account/log in first before donating - otherwise will not be able to update your forum status so it reflects your donation.