Search Engine Marketing -- SEM -- involves efforts related to increasing the visibility of any web page in search engine results. These efforts include search engine optimization, pay-per-click advertising, and paid inclusion. While SEO is built into any given site, paid advertising and inclusion involve paying for "guaranteed" inclusion. High placement or ranking, however, is not guaranteed.
While we don't typically recommend paying for inclusion in search results or other directories, sometimes it does seem necessary. There are online directories for everything. If your directory of choice requires a membership or listing fee, you should weigh the cost versus the potential benefit to determine whether you are willing to pay to have your website included in any given directory.
There are plenty of ways to increase your site's likelihood of being found on the web without paying extra for it. We typically submit our clients' site information to Google, Yahoo, MSN, and DMOZ as part of our web development work. For a small fee we will also submit site information to secondary search engines like AOL, A9, Ask and Excite. We can also recommend our clients for listings in online directories like YP.com.
While there is absolutely no way anyone can guarantee the position of your website on search engine results pages or directory listings, there are many methods for getting traffic to your site. We consult with our clients to determine whether they are interested in pay-per-click advertising like Google's AdWords, or other similar services. We have found that the best results come by working through several SEM methods, and being patient. The web changes every hour of every day, and the best sites are the ones built on a robust framework of best practices for the web.