hey Cider..

when browsing the addons area https://addons.mozilla.org/en-US/firefox you will notice that when the addons are approved there is a Green "Add to Firefox" button, if the "Add to Firefox" button is Yellow and has something along the lines of "Hasn't been approved by Mozilla" and caries a warning about un-signed extensions can be harmful etc etc

when there yellow it means they haven't been reviewed by Mozilla so alot of malware/spware writers are using this Timeframe to upload a malicious addon thay may or maynot work and to get as many people to install the addon before it get's Reviewed and removed from the addon site.