isv.wikipedia.org/wiki/Glavna_stranica

This sentence is outdated because Wikimedia changed how logged-out editing works.

Official MediaWiki help now says that Wikimedia projects allow editing with or without creating an account, and that when someone edits without an account, the edit is attributed to an auto-generated temporary account. It further explains that, under this system, the editor's IP address is hidden and only the temporary account name is shown publicly.

The Wikimedia temporary-accounts FAQ likewise says that any time someone publishes an edit on Wikipedia or another Wikimedia Foundation site without logging in, a temporary account is created automatically, and the IP address can then be accessed only by authorized staff and community members.

So, while creating a registered account can still be useful for many reasons, it is not necessary merely to avoid having your IP address publicly displayed. Logged-out editors now get temporary accounts for that purpose.