I've just discovered that UsingEnglish.com has recently been mentioned in a conference, the "Assembly for the Teaching of English Grammar Annual Conference", July 25-26, 2003, in their "English Language Resources on the Internet: Sites for Sore Eyes" section.
This is a very good indication indeed of the reputation the site as a whole is starting to have. The citation from their online program gives the following description of the site (I'd love to know what they actually said during the presentation):
“English Language Resources.” 2003. Using English. 23 July 2003. http://www.usingenglish.com/resources.htm. (A huge site most of which is devoted to ESL, but many topics and links are also appropriate for native speakers of English.)