Most of the links in this site are to other, not necessarily commercial, sites. Very nicely done. Visit the Special Exhibitions or browse through the Artist Index. The list or terms in the Glossary is brief but the explanations of those terms are detailed. The links on the timeline lead you to beautiful images which may or may not be accompanied by relevant text.
Annotations are brief and useful.
Familiarize yourself with this site now and it will come in very handy later. As enquirers explore the terminology of a new discipline and come to understand the generally accepted reference of terms, this will serve as a basis for learning and communicating in that arena. Searchable, browsable, and scholarly. Be sure to read the introductory material as jumping in the deep end may leave you feeling confused, at least that's what happened to me. This searchable site also offers scholarly reviews, a job guide, and resources for teachers.