Heartbleed Bug

For those who have not yet heard the buzz around the internet, there was a very dangerous bug discovered on some websites which may allow your personal information such as usernames and passwords to be compromised. The websites which are vulnerable to this bug, which has been dubbed the Heartbleed Bug, are those which employ certain compromised versions of OpenSSL. OpenSSL has released a short statement on the matter, in which they stated:

A missing bounds check in the handling of the TLS heartbeat extension can be
used to reveal up to 64k of memory to a connected client or server.

Only 1.0.1 and 1.0.2-beta releases of OpenSSL are affected including
1.0.1f and 1.0.2-beta1. 

Affected users should upgrade to OpenSSL 1.0.1g. Users unable to immediately

upgrade can alternatively recompile OpenSSL with -DOPENSSL_NO_HEARTBEATS.

This bug was largely fixed a week ago, when it was originally made public by CloudFlare, after being discovered by a few folks over at Codenomicon.

For users who are worried about their personal information, the best practice is to change your passwords. However, before running off and changing all of your passwords, make sure that the site in question has patched the issue, or else you are just changing your password on a system which is still vulnerable. Instead, I suggest heading over to Mashable's article, where they list the systems which are affected, and if you should change your password or not. They also leave a little note, so you can better understand the state of that particular site.