Date::Holiday::PT changed to Date::Holidays::PT (internationalization issues, and yes, there were some people using that module).

Lingua::Identification changed to Lingua::Identify (but I can't seem to find the first one on my backpan, so I guess by that time I had it only in my homepage; and yes, people were using it too).

This last one also had a considerable API change, at some point (and a big internal change, too).

One last thing regarding namespace/API changes: do it as soon as possible! :-) The least users you have the easier it gets! :-)