I surely think the previous posts of mine Mozilla Extension #1 and Mozilla Extensions #2 was of some help and this link was dugg good number of times. I got inspired by this and I am continuing to post two more extensions that I felt very useful, and of course you surely love them.
Many are interested in becoming members of many sites we all are aware when regestering to any site it surely requires name or E-mail id. I have both my user names and mail id's long. So I found this extesnion PasteEmail which saves the mail id and up to 15 text fields, and you can paste them by right clicking on the field while filling up the form. Thanks to ChuckBaker You can preview the PasteEmail.