As part of the policy development for new gTLDs, ICANN is planning to allow single character names at the second level for new gTLDs (e.g a.example, b.example, 1. example).   For existing gTLDs ICANN reserved single characters names at the second level.

Existing gTLD registries are beginning to seek contract changes to allow release of single character names at the second level as well.   ICANN has now approved the release of single character names for .coop and .mobi.   Requests for change are also expected for .biz and .com.