Rappler has a special feature on the security, vulnerabilities, and constraints of passwords:
Unfortunately, technological progress has made brute-force password-search tools, like “John the Ripper” extremely effective. As a result, attackers can find passwords fairly easily by following their electronic fingerprints.
Attackers can also capture passwords, for example by tricking users. “Phishing”encourages users to connect to a website that imitates one they were looking for, thus allowing attackers to steal login information (e-mail and password).
Many social networks, shops, banks and other online services require user identification and authentication. It is important be sure we are connecting to the genuine website, and that the connection is encrypted (lock, green color in the browser address bar), to prevent passwords from being compromised.