Two different SEM disciplines have developed to help organizations achieve visibility…

1. Search engine optimization (SEO)

SEO is aimed at achieving the highest position practically possible in the organic listings on the search engine results pages. To do this you need to define a list of keyphrases to work with.

In Google, Yahoo! and MSN Search, the natural listings are on the left as shown in Figure 1 and Figure 2, although there may be sponsored links above and below these results (typically differentiated to the consumer by the title ‘Sponsored Links’).

There is no charge for organic listings to be displayed, nor when a link to your site is clicked on. However, you may need to pay a SEO firm or consultant to manage optimization, and the ongoing work needed to make your website appear higher in the rankings.

Other reasons to employ SEO expertise include managing security of content, copyright ownership, reputation management and user experience management.

2. Paid-search marketing

Within paid-search marketing there are two main alternatives:

(a) Paid-search engine advertising (aka PPC / sponsored listings).

These are highly-relevant text ads with a link to a company page and some ad text, displayed when the user of a search engine types in a specific phrase. These ads are displayed in the sponsored listings part of the SERPs as is shown in Figure 1 and Figure 2.

As the name suggests, a fee is charged for every click of each link, with the amount bid for the click determining the position.

Google Adwords factors in a ‘quality score’ based on the clickthrough rate for each ad, meaning that an underperforming ad might not make it to the top.

The most important PPC services are:

• Google Adwords (http://adwords.google.com)
• Yahoo! Search services (http://searchmarketing.yahoo.com/) / Overture (http://www.overture.com)
• MIVA (www.miva.com)
• MSN Ad center(adcenter.microsoft.com)

(b) Content-network paid-search advertising

Sponsored links are displayed by the search engine on a network of third-party sites. These are typically media-owned sites such as online newspapers or affiliate marketing sites.

Ads may be paid for on the basis of clicks (this is most common) or on the number of ads served (CPM basis).

The most important content network services are:

• Google Adsense (http://adsense.google.com) for site owners, provided through Google Adwords for advertisers.
• Yahoo Publisher Network (http://publisher.yahoo.com/) for site owners, provided through Content Match for advertisers.
• MIVA (www.miva.com).

Paid-search advertising is more similar to conventional advertising than SEO, since you pay to advertise in ‘sponsored links’.

But there are big differences…

• With PPC, a relevant text ad with a link to a company page is displayed as one of several ‘sponsored links’ when the user of a search engine types in a specific phrase. So, the first difference to conventional advertising is that it is highly targeted – the ad is only displayed when a relevant keyword phrase is typed in.
• With the PPC approach, you don’t pay for the number of people who see your ad, but you only pay for those who click through to your website (hence Pay Per Click).
• The prominence of the ad is dependent on the price bid for each clickthrough, with the highest bidder placed top (except in Google, where clickthrough rate is also taken into account)।