On Page Optimization is optimizing your website in a way that it can rank better in search engines and improve visitor satisfaction. One must take care about website user interface which should be always targeted for visitors not for search engines. Off page optimization is very much helpful in improving SERP position and effective traffic. It plays major role in getting active traffic and quality backlinks. By using following ways we can get effective traffic. - Article submission - Link wheel - Forum posting - Blog Commenting - Press release - Directory submission - Social book marking - Classified Submission etc.
On page optimization is used for optimize the webpage whereas off page optimization is used for optimize the links to get quality backlinks..
It is not off-line and on-line, It is on-page and off-page SEO. The on-page search engine optimization factors under the webmaster's direct control. It is related to page structure and website. Off-page SEO is process to increase visibility on search engines by link building activities like Article submission, Blog posting and commenting, Forums, Directory submission, Social bookmarking etc.
The OP has only ever made this one posting, so as they are unlikey now to return, I think we can assume that they were referring to on-page and off-page. That being said, we have had clear explanations of what the difference is between them. If anyone is still unsure, they can do a Google search. So for anyone viewing this thread now, please read it before posting, and only post if you have some new perspective to add, i.e. please do not repeat was has been said already.