*NEW REVIEW*
5 years ago I gave up with this add-on, because it was slowing my browser to crawl. Now it was even worse, because right after installing the whole machine was stuck so badly that I couldn't even switch from GUI to text console (I'm using Linux - it takes something really wrong for this to happen) and try run "killall -9 firefox-bin". And the HDD kept churning something (I guess it was swapping! I have 16GB RAM, my machine almost never needs to use swap space!).

Finally I killed the power (thanks a lot, I had a lot of stuff open in other applications! Thank god FireFox offered to reload my crashed session).

When FireFox then loaded, I went straight to the add-on manager and disabled WOT. I didn't want to see if it would behave any better after restart - I don't like messing with rebooting, especially by force from power button!

I gave you 1 star last time and now I would love to give you zero, if possible, because that was not acceptable!

Otherwise your add-on is great, and might run smoothly on this machine, if it's code was *written well*. Your add-on after all is not that complicated, it shouldn't have ANY effect on speed. And my current machine also has add-ons that run smoothly despite of being quite heavy on resources.

*MY OLD REVIEW FROM 5 YEARS AGO*
First I really thought I was going to like it. I've used WOT through NoScript to check which sites to allow and sometimes to check the site I'm on via FlagFox...
But under only couple hours I noticed that my whole browser had slowed down, I was getting "script busy" errors, and yes, they were from this plugin.
It's not a brand new machine, only a year old or so, I think it's 1,6Ghz dual-core Atom CPU netbook with Windows 7 (uh, I normally over install linux right away) and with FireFox 30.0
Disabling the plugin fixed the problem with one swift browser reboot.