Org's method for capturing new items is heavily inspired by John Wiegley excellent remember package. Up to version 6.36 Org used a special setup for remember.el. org-remember.el is still part of Org mode for backward compatibility with existing setups. You can find the documentation for org-remember at http://orgmode.org/org-remember.pdf.
The new capturing setup described here is preferred and should be used by new
users. To convert your
org-remember-templates, run the command
M-x org-capture-import-remember-templates <RET>
and then customize the new variable with M-x customize-variable org-capture-templates, check the result, and save the customization. You can then use both remember and capture until you are familiar with the new mechanism.
Capture lets you quickly store notes with little interruption of your work flow. The basic process of capturing is very similar to remember, but Org does enhance it with templates and more.