What's the difference between SEO and SEM?

The technical definition of SEM also includes optimizing your sight for search engines and combining that with buying various advertising methods to attract visitors.

Search engine optimization includes both on-site and off-site maneuvering without paid advertising to attract links to your site. On site optimization also means adding new, fresh and relevant content as well as showing activity on the Web site.

The formula is complicated and know one outside of the search engines really knows the intricacies. We keep guessing about what works and what doesn't. It is both an art and a science. One must add creativity and intuition to all the statistics based solely on mathematical formulas called algorithms.

Karl gave a good explanation. When we do internet marketing for our clients, we don't necessarily focus on SEO. Our strategy for website marketing is to create a lot of great (relevant) content like articles, videos, podcasts, buyers guides, blogs, facebook and twitter.

All of those things drive the prospect to the main webpage, or it has a specific call to action such as request your free needs analysis, download a whitepaper call us etc.

SEM - It includes both SEO and PPC.

There is a big difference between the two. Search Engine Marketing can cost you a pretty penny to get to first page, but you get there faster.
Search Engine Optimization is free listings. Takes longer but is do-able.
My company used The FarPoint Alliance - http://www.farpointalliance.com - the cost was very reasonable, especially for a small business.
Also consider this, if they are NOT on first page in free listings, how can they get you there. Just check ONLINE MARKETING EXPERTS or BETTER SEARCH RESULTS. Highly recommended

Go Karl! Here is Bing's definition from http://www.bing.com/toolbox/posts/archive/2009/12/01/seo-and-sem-basics.aspx

Search engine optimization (SEO) refers to organizing Web site content and using other non-paying methods to help improve a site's placement in search engine results, and is a subset of search engine marketing (SEM), which also includes buying keywords or sponsoring search results to artificially elevate a Web site's placement in search engine results.

Close but no cigar boys. SEO = Search Engine Optimization

SEO is on page work that organizes and presents your relevant terms in a manner that both human visitors and search engines can understand.

According to Google this is "Organic" SEO with organic being based almost entirely on relevance.

The flip side to this is that of the PPC (Pay Per Click) search results listings that are placed according to who pays the most, and not the relevance.

Building links will build traffic.
Building links will improve your PR (PageRank).
The more PR you have the more often your site will be visited by Google.
The more visits you get the more often your newest material will be added.
The more new material you add the better your silo content and each new addition is another chance for a good ranking.
The better your silo content the higher the ranking.

Everything offpage is SEM (Search Engine Marketing).
The "O" in SEO is "Optimize".
There is nothing to optimize off page.
You can construct links. Links build traffic. You can construct optimized links out of anchor text, but the anchor text is determined by on page content.

If you are promoting on a blog you are doing SEM.
You want to write optimized content for search engines to find.
Adding "clouds" of "tags" is SEM.. you are not optimizing anything.. You are adding keywords to "help" with search.

best,
Reg
nbs-seo.com