Is it true that JSTOR only features articles that are over three years old? Why is this?

Many journals in JSTOR have a "moving wall," which means that content from the most recent 1 to 5 years of those journals is not available in JSTOR. A number of publications in JSTOR, however, have recently made their most current issues available. Other journals' most recent content in JSTOR is now also indexed, but only available in full-text from another library-licensed database. To find the full-text for those articles use the UC-eLinks* button:

UC-eLinks button 

So while it's no longer entirely true that JSTOR only features articles over three years old, if your research focus is current scholarship, Academic Search Complete and Google Scholar may have more relevant results for you. JSTOR remains a fantastic source for historical interdisciplinary research, and many of their journal subscriptions span back to the date of a journal's first publication.

* For details on UC-eLinks, see What is UC-eLinks, and how do I use it?