Bitcoin Forum

Someone advised me not to use any 'thin' wallet because they could easily expose my identity to 3rd party. I never heard about 'thin' wallets before.

What wallets are considered 'thin' and why are they insecure?

https://bitcoinhelp.net/know/more/definitions/thin-client

It's pretty much another word for SPV wallet.  Probably was used in early days.

The security issue with SPV wallets is that you're relying a lot on the servers.  They can see your IP and addresses, and are also responsible for giving you the information of your wallet's addresses (but no, they don't see your private keys).

Most people refer to them as light wallets.

They use less system recourse (especially HDD space, the blockchain is quite bloated by now) and are generally easier to use and handle as you don't need to think about synching.

Thin wallets may be the name used in past for light wallets. Electrum is actually an example of light wallet where you don't have to download whole bitcoin blockchain to do bitcoin transaction. However i don't see much difference between using web wallets and light/thin wallets as both rely on remote server/bitcoin client and store users detail on client/user sides rather than in their server. All online wallets can be considered as possibly insecure so it is always advised not to store large no. of bitcoin in web/thin/light wallets.

you should know that security and privacy are two completely different things.

thing wallets or SPV clients are secure as long as it is a well known wallet like Electrum which is open source and many people are checking the code.

so i am sure that someone either made a mistake in using the term or you misunderstood him about security.

but on the other hand about the privacy as it was said, they may not be the most private wallets since for example when you connect to an Electrum server to get your updated balances and latest blockchain headers your wallet will tell the server all your bitcoin addresses (only addresses never private keys or any sensitive data) so that server can log all your addresses and know these are yours and your IP is xx.xx.xx.xx

Also known as light or SPV clients, thin wallets are bitcoin wallets that function exactly like Bitcoin Core, however with one main change. The blockchain data is stored elsewhere. This means you store nothing on the computer but the barebones client and your wallet file, external servers provide the rest. However the external servers you connect to may or may not be malicious, feeding you incorrect information. But not to worry, your bitcoin is safe. Just remember to use a trusted server or cross-reference with a blockchain explorer like blockchain.info

So that means a thin wallet is more or less an online wallet? Just that there are less risks of getting hacked... ???

Yes that is correct. When such wallet are setup on a clean PC and the user is sure their PC is clean they are as good as hardware wallets in that time. With the passing of time if your PC gets infected you risk to lose your coins even with these wallets as when you send a payment the seed is decrypted for a few seconds and is stored in the memory of your PC. For peace of mind buy a hardware wallet although electrum and multibit when used like they should be used in a clean PC are great too for storing your coins.