There are a plethora of options for fundraising now on the Internet . Some are better than others . For example, while GoFundme charges 5% for their platform (on top of processing fees), You Caring does not charge any platform fees. Besides popular sites like GoFundMe, or KickStarter, there are the payment processors themselves, such as PayPal , who are getting in on the act to take a percentage. Other payment processors like WePay are the underlying payment processor of these crowdfunding sites. And as the competition heats up, it's hard to keep track of all the available options. To wit: Stripe, the payment processor, offers Donorbox, the platform on top of their service. While sometimes it may be appropriate to use an external platform or processor to do your fundraising, here we will focus on the free software options that enable organizations like non-profits to do their own fundraising.
CiviCRM is just such an option. Both the Free Software Foundation and Wikimedia Foundation use CiviCRM to manage their fundraising by using CiviCRM. The reason for doing this is that CiviCRM offers a wide choice of underlying payment processors  so that you can use the "mechanical" service of your choice, while also retaining all the data about contributions and donors internally so that you don't have to outsource the data about YOUR donors/members/clients.