What is flexible, fluid or liquid design?
The definition of fluid or flexible design is that it is a technique to make page elements adjust on window resize. This means that a website takes up all the space allocated to it by the browser. This contrasts fixed design which tries to force a constant width no matter what screen space is allocated by the browser.
Strawman argument: Flexible is bland
"Flexible design does NOT mean delivering colourless plain text to anyone who cannot use The One True Rigid Fragile Creation." -- Alan Flavell
The "Flexible is bland!" argument has occurred more or less constantly since about 1996. It was incorrect and silly then, and it is now. No-one can be blamed for designers who can't create a good-looking and flexible site (apart from the designer himself). It isn't as if it was impossible. The straw-man argument about flexible and/or standards compliant sites is very old, and just as silly.