Good points, both. It may be that we don't actually _need_ `:event_name`, just `:external_name`, but, given that this method is called in a number of places and is fairly general-purpose, it probably makes sense to do both.

Re: JavaScript, I think that if we keep both, there will be no compatibility problems. The compatibility issues would arise because browsers would have an old copy of `vendor/assets/javascripts/meta_events.js.erb` cached locally that wouldn't know to look for `external_name`. As long as we keep `event_name` around, all it will mean is that there will be a gradual transition from the old-style fully-qualified names to the new-style overrideable names (if you override them), as browsers purge that out of their cache at whatever interval the developer using MetaEvents has set when they deliver that JS file.

Now that I'm thinking about it, that's probably the most compelling reason to keep them both around. :)