Defective verbs-About.com

http://spanish.about.com/od/conjugation/a/defective.htm

There is one daily email I subscribe to,  from About.com.  I never cease to be amazed at the scope and detail of some of the topics covered in this email.  Today's mailing from Gerald Erichsen  (About.com) is, among other things,  a detailed discussion of   "defective verbs." Or verbs that aren't conjugated in every person.   As I try to surmount the challenge to speak decent Spanish I find seemingly minor grammar issues such as this very interesting.  Blog readers interested in improving language capability might consider signing up for this free daily mailing.