mongoid/mongoid — comment on commit 5f57f3d39f6a9fbdca157d7d38443b23d42e73da
File: lib/mongoid/finders.rb line 117
By DouweM:

That's correct, but I believe the Mongoid `find_by` (notice it's not `find_by_*`) is supposed to function exactly like `find`, except for accepting a hash of conditions. It not being `find_by_*` and it not behaving like ActiveRecord is actually a conscious decision, as @durran has said [here](http://groups.google.com/group/mongoid/browse_thread/thread/794b99f1d135b46b).