From time to time, I would like to make a small financial contribution to the Arduino project. Unfortunately, you don't appear to be able to accept contributions via PayPal. If you can't take PayPal, I can't contribute.
Why don't you accept PayPal? It is after all, very widely used.
Thank you for supporting Arduino in other ways. We are looking into a way to integrate Paypal but looks like to very easy to integrate in the short term. Be sure it will be integrated but no ETA yet.
The main question about payments by credit cards that you should maintain particular security level. May be you do. But how I can be sure that is really safe. You should add PayPal (IMHO).
Now we have full https support and we never store CC info.
We are DSS compliant and we use stripe as gateway payment service. You credit card data are sent directly to stripe and we work with a secure temporary one transaction only token.
The support for PayPal is something we want to have but not in our roadmap yet.
Another way to contribute is buying our products from the official stores.