The Good Access to vast amounts of information quickly and easily. A scholarly or reliable page can link to an unreliable source or vice-versa. Large graphics that take a long time to load onto your screen. Pages that are not documented well so that it becomes difficult to find out where the information came from.
Hackers can sometimes access and change information without the author knowing it.
Information is sometimes taken out of context. Pages that are biased politically, sexually, racially, etc. By applying these criteria to the web source, you can attempt to evaluate its reliability and usefulness to you. Overlap of criteria sometimes makes it too hard to apply individually, so we need to combine criteria or just try to apply some points and not all points.