Imgur has been breached, and so may you

https://haveibeenpwned.com

Go to the url above to see if you're affected by this databreach. If you are - please make sure to change your password (both on Imgur as well as any other site where you might have used the same password).

Why are you only hearing about this now? 
Whilst the breach occurred in September 2013, sometimes there can be a lengthy lead time of months or even years before the data is disclosed publicly. "Have I been pwned?" will always attempt to alert you ASAP, it's just a question of how readily available the data is.

As with any data breach, the usual advice applies: consider the potential risk to yourself based on the types of data exposed. For example, if passwords were compromised then go to the impacted site and reset yours immediately plus, of course, ensure that you're not reusing that password on any other sites. Please note that it is not possible to retrieve the passwords themselves from HIBP.