Compared to the old fashioned way of conduction paper surveys, web surveys are cost effective and produce fast and accurate results. Keep in mind though that creating a web survey requires just as much planning as a paper dito. Below is a simple walk-through.
characteristics
behaviours
knowledge
Surveys are conducted to gather data - characteristics, behaviours and knowledge - of a specific population relevant to a specific problem. This means that the first thing you must do, is to clearly identify your research objective. That is, to answer the question "why am I conducting this survey?". The more fuzzy the answer to this question is, the wider your research scope will be, and the less useful your results is likely to become.
This is perhaps the most difficult part of conducting a survey. The difficulty of asking questions stands in relation to your research scope - if your scope is narrow enough, the answer to this question should be pretty obvious. Anyway: