They were more popular early in the late 19th and early 20th century than they are now, but people still like to compose and solve them.
Word squares come in two traditional types, regular and double.
Eric was using about 63,000 words when he discovered his square. This makes this square arguably the second-best ever discovered. There are about 1000 9-squares known, all of which were constructed by hand except for the seven noted above. Almost all of these use very obscure sources of words. As a general rule of thumb, if you discover a new square via computer search, it is probably going to be of high quality, since it is hard to obtain computer-readable word lists that contain very obscure words.