Works fine for me....

Are PM's enabled on your system?

Admittedly I should be checking ;)

I have PMs setup using Promotions, not everyone can use them.

Is the current version free of any known bugs, ready to run on a 45,000+ member website? Do the phrases used follow proper grammer and spelling?

It is now ;)

Just updated to fix a PM usergroup permission bug. Also to reduce the size of the datastore (which caches all plugins!) and to allow eAccelerator to cache and compile, etc :)

I've just nabbed the last two hard-coded phrases too, and yes my English is adequate.

Thanks for the update :)

Couple of questions:

Can users turn this feature off if they don't want to be part of it?

What happens if the secret admirer is on someone's ignore list?

I haven't written such functionality, but there's no reason you couldn't create a custom field and then edit the MEMBERINFO template so that the link to admire that person doesn't show if they have decided to turn it off.
Currently it would still admire that person. I hadn't thought of this scenario (ignore lists are barely used on my forum).

Not sure what you'd want to happen in this case... the person who admires should think they've succeeded, but the person receiving shouldn't know about it.

Would silencing the communication be enough? But to let the admiration go through?

Where do we change the text sent via PM's/Emails?