Promote This! is a Movable Type plugin that Byrne Reese created in 2006 or earlier. It was one of the first plugins to provide tags to support a wide range of social bookmarking and promotional services.
Because Promote This! has been around for 7+ years, it’s present in a lot of older Movable Type 4 installations. After6 decided to update it because helped facilitate upgrades of customers’ older Movable Type-based sites, and made it easier for these customers to stop Movable Type 4.
There are many alternatives to using Promote This! in new Movable Type projects. However, updating this plugin decreased the cost and increased the likelihood of completion of quite a few MT 4 to MT 5 upgrades.