Perhaps this is more for the research geeks, but Alexandru Cernat blogs at Talk Methodology about online surveys of the general population.
This is an important topic, because there is continual demand to deliver robust results at a reduced cost. All methodologies have advantages and disadvantages. Online surveys can be cost effective, and there are other benefits such as the ease of displaying video and high resolution images, and the ability to use clever interactive question formats. It can be difficult though (but not impossible) to reach those who don’t have access to the internet at home or who don’t subscribe to an online panel.
Alexandru summarises his thoughts about a conference on the topic. Conference papers can be found here. The conference was held in February 2013.