Food for thought for the advocates of liquid democracy.
In many Western countries, options for citizens to influence public services are increased to improve the quality of services and democratize decision making. Possibilities to influence are often cast into Albert Hirschman’s taxonomy of exit (choice), voice, and loyalty. In this article we identify delegation as an important addition to this framework. Delegation gives individuals the chance to practice exit/ choice or voice without all the hard work that is usually involved in these options. Empirical research shows that not many people use their individual options of exit and voice, which could lead to inequality between users and nonusers. We identify delegation as a possible solution to this problem, using Dutch health care as a case
study to explore this option. Notwithstanding various advantages, we show that voice and choice by delegation also entail problems of inequality and representativeness.
For those who are willing to read more than quotes and blog posts, the full paper is here [PDF].
DemocracySpot 
“Liquid Democracy” as envisaged by the chap that coined the term, is NOT about delegative/ proxy voting.
See here http://seed.sourceforge.net/ld_k5_article_004.html where he writes:
“Other systems similar to LD have been designed, but as far as I know they employ vote proxying, rather then answer recommendation”
And here http://campaigns.wikia.com/wiki/Liquid_Democracy where he re-iterates the same thing
“i’d just like to stress the difference between vote proxying and vote recommendation. one’s “pull” and the other’s “push”, and that’s a big part of what makes liquid democracy unique. with liquid democracy, people can request recommendations from multiple people, and from there they can do all kinds of things – take the average, ignore some recommendations, ignore all the recommendations and vote their unique conscience, etc. with proxying, you can’t do that, and that’s why proxying isn’t enough. “
Fair enough. But then it really starts to look like democracy as we know it.