I think what tye was trying to say is that you misunderstand what readmore tags do. They are ignored and the full content is shown when you are looking at the node itself. They only take effect when viewing a group of nodes (as on the Seekers of Perl Wisdom page, or an ancestor of the node containing the readmore. For example, try Re^2: readmore in snippet description and then its parent Re: readmore in snippet description.

There is no page that shows multiple snippets, so readmore is useless for them.