What are Drive-by-downloads and how to avoid getting Malware in the first place

There's good article here which advocates the best advice when it comes to dealing with Malware - "don't get it in the first place!". I accept that most users need a little more help than simply being told that. Adam and Charles(authors of the post) understand this too and hence they give a nice explaination of "skeptical computing" (their term - one worth remembering IMHO) together with terms such as "Drive-by-downloads" and "bundlers". The article is best suited to your friends and colleagues who ask you to fix their machine following their ventures into polluting their machine with dodgy software.