The linked site is an application for sending and discussing links with your friends, not for exchanging money. I think the distinction is quite clear.
I AM NOT A LAWYER AND KNOW NOTHING ABOUT WHAT IM SAYING - TAKE THAT INTO CONSIDERATION WHEN YOU READ BELOW.
IANAL, but it doesn't appear that you infringe on anything. A trademark is only valid for products or services which appear to be, or are similar to, the scope of registration. This can include scope for 'natural growth' into other areas.
All their trademarks seem specifically about the exchange of currency. There is nothing there relating to sharing and discussing links with your friends, or even broader classification which they could most certainly have registered for.
That said, you should speak with someone a lot more knowledgeable than me about it!
