When you develop a wordpress theme maybe you have to use two sidebars which to use them both at once or on different pages. I recently encountered with this problem and i thought that maybe there is someone else in the same situation.
Creating multiple sidebars in wordpress is a fairly easy process. We have to work just on functions.php file. Your default functions.php file should look like this:

Hi. I am Marian, the owner of WPCONCEPT. I am a freelancer web designer focused on web development and i am a big fan of wordpress.
I am from Transylvania, Romania and please excuse my grammar mistakes. I do my best to improve my english skills.