Shilling ranges from an undisclosed paid promotion to simply talking up something you own without saying you own it. The common thread is a hidden incentive: the speaker gains from your buying, and you are not told.
Disclosure is the whole question. Someone who states their position and then argues for it is giving you a view you can discount appropriately. Someone who does not is selling. In regulated markets, paid promotion without disclosure can be a criminal offence, and it is standard practice to assume undisclosed enthusiasm about an illiquid asset is paid until shown otherwise. See finfluencer.
Related: pump, exit-liquidity, finfluencer, social-proof