Is SEM different from SEO, An interesting discussion in forums search engine watch

An interesting thread was started in searchenginewatch forums, A poster asked what is the difference between SEO and SEM, everyone gave their opinion,

Here is my opinion on the same thread,

I agree with tomslick, SEO is part of SEM,

SEM IMO consists of,
1. SEO
2. PPC
3. PFI ( Optional )
4. Link Building
5. Affiliate SE Marketing
6. ROI and conversion tracking
7. Sponsored Search engine listing(some search engines).
8. Shopping feeds ( shopping search engines )

SEO - Search Engine Optimization, Ability to improve a site to make it relevant to Search Engine Algorithm and make the algorithm rank a site based on User queries.

Source: forums.searchenginewatch.com/showthread.php?t=3045

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