If you're looking for a way to anonymously tell your crush how you feel, there are a few different options available to you. You can write a note and leave it somewhere for them to find, or you can send them an anonymous text or email. There are also a few websites that will let you send your crush an anonymous message.
I don't know much about anonymous note to crush services, but I imagine that they're a way for people to send each other notes anonymously, perhaps in order to confess their feelings or ask for advice.
The author of the anonymous note suggests that "crush services" are a bad idea and that people should avoid them. The note also claims that these services are a waste of money and that the people who use them are only looking for attention.