Tumblr, one of the most popular blogging platforms has become ever more popular in the recent years. Tumblr provides a very clean homepage with very easy sign up form. But did you know that you can use this same form for logging in as well?Yes you can simply enter your login credentials in the signup form to login to Tumblr. This feature can be helpful because Tumblr doesn’t give a dedicated login form on the homepage but instead asks you to visit a separate page for logging in. This feature of Tumblr which lets you use the sign up form for logging in can come in really handy.