Sharing a project adds ?ref=yourusername to its address. Opening that link does exactly what opening the plain address does: it loads the project. The tag does not change what the visitor sees, and on its own it does not earn you anything.
The link and the tag are two separate things
The part of the address before the question mark is the project's page. The part after it, ref=yourusername, is only read if the person who opens it goes on to create a UNI account, and it is the same tag used by the referral link on your profile. I shared a competition and it said I would earn a free week, so where is it? sets out what has to happen for a referral to be credited. Read that page before counting on a share turning into a reward: as things stand, sharing a project link does not put a free week or any other credit into your account.
What the tag does not do
- It does not unlock a private project. A private project only opens for its team. Whoever you send the link to needs to be signed in and already added to the project, or the page will not open for them regardless of the address.
- It does not bypass a free viewing allowance. If the person you send it to has used up their free views for the month, the link still lands them on a locked page. Why can't I view this project? covers how that allowance works.
- It does not affect the project's view count. Views are counted from who opened the page, not from any tag on the address.
If the link itself has stopped working
That is a separate problem from the ref tag. A project's address is rebuilt from its title every time it is republished, so a link can go dead even when nothing was ever shared with a ref tag on it. The project's web address changed after I renamed it covers that.
What to do
Share the plain project address if you only want people to see the work. Add ?ref=yourusername if you want a record that the visit came from you, but do not promise a reward for it right now.