Create one or more pages of "teasers". Teasers are like WordPress Posts - except that they generally point to content on some external site
Your teasers are preserved if you upgrade from "Std" to "Pro". You can continue editing and displaying them with the "Pro" version.
This applies to the currently available versions of Teaser Maker (June 2014). We can't guarantee that it will apply to future versions. (But obviously, we don't want you to have to re-enter existing teasers when you upgrade, unless there's absolutely no way of avoiding this.)
No! Teasers are stored in their own table in the database - and have nothing to do with the WordPress "custom posts" system.