It displays in a fixed position on the page which makes it in the users eye and will result in a greater conversion rate with your users. It has an option to not float as well.
All the settings are done through the administrator which can be accessed from the module manager. It's fully workable within Joomla 2.5 and Joomla 3.0.
So if you want an PayPal donation button on your website which will drive more money to your business or charity then the Floating Donate Button is your answer.
Support is provided free of charge with a selection of documentation available to view.
I had some problems to make it work together with BT-login but the suport was great and fixed that right away.
Glad we found the fix to this problem. Strange and bizarre issue but glad I've got it fixed.
Best of luck with donations :)