Normally you shouldn't enable this box, but if you still want to know what people are searching for you can.

The weird symbols can appear due to many reasons:

1. People are actually searching for it.
2. People are probably searching for international songs with non-english names
3. They're client may be old and full with bugs

And there are many more. You shouldn't worry about it.
Also, if you use ultrapeers, you proably won't see many searches.