what is the difference between

Seems like you are comparing apples to oranges...
SEM = SEO (organic promotion) + PPC (paid promotion). It can either be done ethically or unethically.
The concept of ‘paid links’ is purely unethical and hence, I won’t encourage you on it.

Are you referring to "buying links or backlinks"? PPC is not paid links, it is "paid ads".

Originally Posted by seopower

what is the difference between SEM and paid links, and if i but test paid liknks it is also called SEM?

SEM(search engine marketing) is the main methodology of SEO(unpaid).but PPC is the method of attracting people through payment.

In sem we do specific activities.
They are free but you have to pay in paid listing.

SEM one can get both paid and non paid stuff, but in paid marketing one will have to pay for every promotion that one is doing.

Search Engine Marketing (SEM)


Search Engine Marketing is a method of Internet marketing whose purpose is to increase visibility during search engine queries. You can do this by selectively choosing the HTML and website content in order to appear higher in a particular search result. Search Engine Marketing are short texts that appear along the side of a search result. They are referred to as "sponsored links" or "sponsored results"

My advice for you is not to buy anything because Google does not agree with that.

PPC is a part of SEM Search engine marketing. SEM includes email marketing too.

The meaning of these two terms is same. There is no specific difference between them.