A few weeks ago I bought an educational version of Quizlet which allows me to take my daily practice tests online. I love taking tests, and it's been hard to find a product that helps me the most when it comes to studying. I have taken several different products in the past, but the ones that help me the most are Quizlet, Anki, and Crystal Reports. These three products all offer similar functions, but also differ in some very important ways.
Quizlet offers a great web-based app that will allow me to learn Spanish online, with its free website and flash cards section. Quizlet also has a very good paid version, which eliminates ads and allows you to study at home, offline, and even downloads and exports flash cards from other sites. The paid version allows you to save and restore your study data, so you can always go back to it if you need to. There are several other features that I use quite frequently, and having these apps on my phone gives me access whenever I need them.
Quizlet LLC was founded by two former Google employees, Matt Cutts and Greg Marshall. Matt Cutts is the creator of Google AdWords and now works as a consultant helping others start their businesses. He created the first version of Quizlet as a test, and now it's used by millions around the world. I really like Quizlet because you can use it for both free and paid versions. You can import your study sets from Anki or other sources, and you can export your quizzes and test sets into PDF documents. And since I'm a big fan of using apps to make studying fun, I really enjoy using the Quizlet interface and using its various features.