Passwords like those stolen from LinkedIn, owner of the world's biggest professional networking website, may not lead to many accounts being breached because criminals selling the access codes reap as little as US$1 ($1.20).
That compares with banking passwords, which can fetch US$15 to US$850 apiece, depending on the account balance, according to internet security provider Symantec.
The utility of stolen data varied by site, leading to price differentiation, said Francis deSouza, president of Symantec's enterprise unit.
Stolen social-network passwords have limited value to thieves because they generally can't take money directly out of the accounts, he said.
Hackers blocked from using the passwords on LinkedIn might still use them to infiltrate other sites if users access accounts with the same login.