Directory submission is the easiest method of off page technique.It gets you good backlinks...
It can also improve page rank of the website.

Link building is used to get backlinks to the website.Link building is very important part of SEO process.
There are good methods which are used for link building process.

To increase the traffic you should follow off page methods :-

(1) Article submission.
(2) Blog commenting.
(3) Forum posting.

SEO is used to generate traffic to the website and it also optimizes the website.
SMO is used to make awareness of the products or services.

Some of the main SEO benefits are as follow :-

-> It optimizes the website.
-> It generates traffic.
-> It can get you good business.