Remote testing is incredibly useful for websites. After all the worldwide web is just that–Global. Remote testing means that one can get feedback unencumbered by location of participants. Rather than intercepting people physically, one can grab people as they go about their business on the site you are testing, for example. Recruitment is no longer bound to location. And, with sites like Loop11, it is super easy to recruit users. Just one link, and you are ready. Without the need for a synchronous appointment, you can rack up numerous user rests.
There are drawbacks to remote testing. The most important is that one loses much in the way of emotion, expressions, and verbal feedback from users. This can make it challenging to understand the reasons that users click the buttons they click.
However, remote user testing can offer high volume feedback and identify trends. In other words, while you might not be able to say why someone did something, you can pretty clearly say categorically that certain trends are obvious.