For webpages there are at least three levels of quality assessment that may be desirable. The first would be provenance, the second content coverage and the third the quality of that coverage. The "provenance" quality is most easily assessed. Silberg et al. (1997)
proposed the four criteria of authorship, disclosure, attribution and currency. While these are important, it remains true that a site could satisfy all these criteria and still be misleading or inadequate. Clough & Oliver (2002)