I do not proclaim any expertise in the area of online giving. But here are two thoughts from a non-expert.
Carey Nieuwhof in a recent blogpost http://careynieuwhof.com/2013/06/12-cultural-trends-church-leaders-cant-ignore-but-might/ list twelve cultural trends that church leaders should not ignore. Checking in at number 12 on his list is:
The death of cash and cheques. When was the last time you wrote a cheque or paid $500 cash for something? No one does that anymore. But every Sunday most church leaders expect most of their offering to come in via cash or cheque. Is most of your giving happening online? Why not?
You can overlook the British spelling of checks, but you cannot ignore the point. Churches and other non-profits will increasingly receive contributions online. I was shocked to find out how much the online giving at my congregation has gone up over the last 18 months. This has taken place with little promotion on our part.
If it is not easy for your constituents to give online you are throwing away money. Lament the fees if you want. Roll your eyes at the people accumulating airlines miles with their contributions via reward cards. But you must have an online giving presence. Find a reputable vendor and establish a way to give on your website today. Paypal is not enough. Drafts from checking accounts, credit cards, designated giving--you need it all.
Will really large gifts be given online? Probably not. But the person who gives $100 online today might just write a check for $10,000 five years from now.