A donation pledge is a commitment to give at least some specified amount of money over a specified period to charities or other donation opportunities. Some pledges target specific types of people. For example, the Giving What We Can 10% Pledge is a commitment people make to donate at least 10% of their income per year over their lifetimes, the Founders Pledge is a commitment entrepreneurs make to donate a percentage of their profits, and the Giving Pledge is a commitment very wealthy individuals make to donate the majority of their wealth.
Other examples of donation pledges include those associated with the organisations One for the World, The Life You Can Save, Generation Pledge, Raising for Effective Giving, and High-Impact Athletes, as well as Giving What We Can's Trial Pledge.
There are various reasons for or against taking, or promoting, a donation pledge. For example, donation pledges might help people follow through on their altruistic intentions, rather than forgetting to do so or facing value drift. But it is also possible for a pledge to be too constraining, for example, if a person's financial situation changes, if they now want to take risks with their career and thus need more financial runway, or if the donation opportunities they want to give to are not within the scope of their pledge (e.g. if they are not registered charities). (Note, though, that it is often possible to resign from a pledge if your situation changes significantly.)