Entry Page tactics are Sitecore personalization tactics that are implemented on the landing or entrance page of a visit. The most reliable source of information about a visitor, outside of a proprietary third party, is the entry information handed to a company when entering the site.
Search Engine Keywords
A large number of visitors will enter your site through organic search. By utilizing certain keywords you can match user expectations with search results, which provides a more relevant user experience.
Visit Count or First Time Visitor
Most of the time the first time visitor user experience may be very similar to default content; however, slightly altering one of the components could have a dramatic impact for new visitors and may provide interesting information.
Campaign Code Personalization
Sitecore Campaign IDs provide companies with the ability to see which campaign a visitor is responding to and personalize their site based on that data. This is ideal for marketing campaigns which involve outbound URLs such as SEM, Display Ad, event, mail, syndicated content campaign.
The final tactic for Entry Page personalization is leveraging Geo-Location to identify exactly where a user is coming from and leveraging that data for personalization. This tactic may require development work.
Sitecore has built seven powerful and interrelated systems for improving website performance, implementing website personalization and running marketing automation. For more on how these separate capabilities work together, check out The Basics of Sitecore Personalization.