TextMate's snippets allow you to type a few characters, press tab and then get a useful template to fill out. There are defined fields in the displayed template that you can tab between. This feature can be a good time saver. To see an example of how far it can be taken, check out Zen Coding: http://code.google.com/p/zen-coding/ The snippet functionality itself should be in a plugin. The snippets themselves should be definable in plugin metadata.
ACETRANSITION The Skywriter project has merged with Ajax.org's Ace project (the full server part of which is their Cloud9 IDE project). Background on the change is here: http://mozillalabs.com/skywriter/2011/01/18/mozilla-skywriter-has-been-merged-into-ace/ The bugs in the Skywriter product are not necessarily relevant for Ace and quite a bit of code has changed. For that reason, I'm closing all of these bugs. Problems that you have with Ace should be filed in the Ace issue tracker at GitHub: https://github.com/ajaxorg/ace/issues