When you visit any website or URL, your IP address along with other connection details are logged and stored in the server.
Some websites also contain malicious codes, which could download malicious programs or backdoor applications to your computer and use those tools for controlling your computer. If such programs are installed and if the bad guy takes control of your system, he can install keyloggers to get details of your your tube account or any other account for that matter.
So your counter measure is to avoid visiting any links which you are not sure of. If your friends have sent you the link, re-confrim whether they really did send the link, coz sometimes your friends computer could be compromised and the malicious application running on your friends server might have sent the link to you. An awareness of such security issues can be the best remedy.
And welcome to EthicalHacker-Net. All the best,
MVP (Enterprise Security), ISLA-2010 (ISC)², C|EH, C|HFI, CCNA, MCP,
Certified ISO 27001:2005 Lead Auditor
[b]There are 3 roads to spoil; women, gambling & hacking. The most pleasant with women, the quickest with gambling, but the surest is hacking - c0c0n