As you can see from the screenshot, all the language skills are dealt with on the site, together with vocabulary, reference materials and links for further study.
The site is primarily intended for university students who are planning to spend some time in an English-speaking university. However, all English students at an intermediate level and above can benefit from the tons of activities the site offers.
I especially like the listening and speaking sections, as they provide strategies that may come in really handy for learners to make headway in these skills.
