Be on the lookout for anything unexpected in your inbox after 711 million unique email address "Many containing passwords" have been made freely available on the internet in the last few days. This is being reported as the largest documented data dump to date. This data can be used in a variety of ways.
Worth mentioning a couple of important security practices:
DON'T REUSE PASSWORDS for different services, otherwise if www.sarahsmuffins.com.au gets hacked because Sarah doesn't know much about security then the bad guys will get access to all your accounts on the entire internet. Consider a password manager like LastPass or RoboForm.
Don't just click on links in emails, at least hover first to see where the link goes, if its an email from Telstra and the link is to www.getyourvirushere.com then don't click. If you are unsure just don't click it at all. Phone or email the sender from a new clean email seeking more details.