Video of 1.7.2.5 with glitches at Stary Sobor. Multiple flush attempts and very clear view of dead soldier artifact sources at 0:42 http://youtu.be/iPt05zGut3c
In the context of digital images and video the term artifact often refers to one of two things; Pixelisation or other unwanted results caused by over compression (images/video) and/or rapid movement/scene changes (video). You will have seen this yourself on digital TV, youtube or static images. Badly shaped/broken polygons caused by math errors due to hardware faults or geometry errors - this is what you are seeing in DayZ The artifacting people are talking about here just means that you are seeing a lot of artifacts as a result of something going 'sproing'. For more, google for '3d artifacts' or 'image compression artifacts' etc.