This malicious Google Chrome plugin Imgur Uploader is now spamming users with ads on different websites you visit.
If you have this plugin made by "ok.ru" - uninstall immediately!
Plugin url (do not use!):
https://chrome.google.com/webstore/detail/imgur-uploader/hgmpmjpekinnebjgnakcahjikbomnmlb
This is what it looks like:

Thread on reddit full of pissed off users today:
https://www.reddit.com/r/technology/comments/4lltgu/psa_imgur_uploader_is_injecting_ads_on_google_and/

I began noticing them just now - thought I'd warn you folks. :)