a)I probably spent almost an hour reviewing this site. It's a massive website with an overwhelming amount of links, but I mean that in a good way. I reviewed many, many topics, ranging widely across the board from our ex-President Clinton's initiatives on math education to the religious applications of math (like Islamic star patterns) to sites about very basic math. Some websites had things I could try out or follow along with and others were purely informational or maybe didn't actually concern applications of mathematics, instead being about understanding of topics surround math, like politics and educational funding.
b) This website is sort of an imitation of what MERLOT itself is, which is a collection of links that can all be used for different types of learning and teaching. As a result, though all were valuable, not all are equally great. Therefore, the educational value of the site as a whole is tremendous, however individual sites would have to be judged alone. And like anything else, some seemed to have more effort put in to them than others.
c) I think that as a teaching tool, it would be useful for Math G students especially who spend a lot of time understanding what a wide variety of topics are mathematics. The site gives a sense of having a bird's eye view of the field of mathematics, as broad and immense as it is, with all it's different topics offered and varieties of disciplines. Additionally, it's also beneficial for both students and teachers to be able to have one place where so many resources are available.
d) The very front page of the site was organized well, but not great. What does make it good though is how different search options are utilized, as things can be browsed either by topic, type of resource or level. Most websites I saw were very easy to use or follow.