Omeka is a platform used to share digital collections and create online exhibits using those collections. This platform is available either by self-hosting or using a hosted service. There are advantages and potential trade-offs with each solution that you might embrace. If you decide to self-host, you will need server space with a LAMP (Apache, MYSQL and PHP) stack. Alternatively, you can also self-host via a paid hosting service, such as Reclaim.
Omeka offers several versions of its platform. Omeka Classic is designed for a single site around a general theme, argument, or research question. With this version, users have access to numerous themes and hundreds of plugins to customize their project.
Omeka S was created for institutions managing a sharable resource pool across multiple sites. While Omeka Classic uses Dublin Core, Omeka S implements multiple vocabularies and facilitates linked open data.
Lastly, Omeka.net offers something like a demo version of Omeka Classic. Through a free trial, users get access to one Omeka.net site loaded with a limited number of themes and plugins. It is useful for institutions with limited hosting options, but also can be utilized by instructors who would like students to create a digital space for coursework or class projects. After the initial one free site, Omeka.net becomes a fee-based service due to hosting.
