Since I first mentioned ProProfs' Flashcard and Quizschool sections back in March, they've kept improving the site!
The biggest news would have to be the addition of a very complete free SAT preparation section. The site features a comprehensive collection of SAT preparation material (covering all three major areas of the exam) that includes study guides, flash cards, practice questions, and even simulated exams. Quizzes, videos, blogs, wiki and interactive forums are also provided. I'm more than 2 decades past my SATs, but I still remember some of the expensive SAT classes and software with which I worked, so I must admit to being jealous that such a rich free resource didn't exist at the time.
My one original complaint about ProProfs in the original entry concerned the ability to post quizzes and flashcards on a website or blog:
Unfortunately, there is no simple embed code box, like the ones you find on video sites.They've not only been working on the site, but listening as well. When you begin flashcards, such as this Spanish 2 set, you are now given an embed code!
The embed code feature isn't yet available in the QuizSchool section, but will be added shortly.
I've listed more than a few flashcard sites here on Grey Matters, but the ProProfs site is quickly becoming a standout site and a very valuable resource.