link building is one type method of seo.
advantages:-
1.link reputation for pr
2.link reputation for traffic generation.
3.link reputation for reliability and faith.
4.link reputation for financial advantage.

best way to increase traffic
1.directory submission
2.article submission
3.blog comment
4.blog submission
5.forum posting

benefits of email marketing
1.create dynamic visual content
2.communicate instantly
3.reach anyone
4.benefits from forwarding
5.build relationship
6.target specific customer.