whendidyoujointwitter.com is a free service which trace the joining date of Twitter user within seconds.It is useful to find out your friends Twitter joining date too. The funny site is created by Created by Neville Ridley-Smith. So visit whendidyoujointwitter.com now.
howoftendoyoutweet.com is similar service which helps to find out the average tweets of a user. Just enter any username to the text field provided in home page and wait for one second, the site will pull tweets average rate from Twitter and show it for you. Dont forgot to visit howoftendoyoutweet.com also.