If you're talking about airdrops and ICOs, I would definitely not recommend giving out your KYC information. Who knows that those projects would do with your information? I know there are reputable ICOs and airdrops out there, but I personally wouldn't take the risk.
If you're talking about KYC for exchanges though, I'd probably consider it, but it still completely depends on how bad I need the service and if there aren't decent alternatives.
Kyc is important to identify our details.The main purpose of KYC solutions is to prevent unqualified people using a service that they are not authorised to use. Examples of such people could include minors, undocumented immigrants and people with criminal histories.
This, and also to prevent people from taking advantage of airdrops and such.
I couldn't agree more, the question whether you TRUST that company or not !...