Flashplayerupdating.com is a fake pop-up about the outdated status of your Flash Player. In fact, you might have the latest version of your Adobe Flash Player ever, however, this fake pop-up may still come up. Clicking it is very dangerous, because at this time of the year many adware programs and potentially unwanted utilities are spread though this method.
The site flashplayerupdating.com is thus very dangerous for you. If you see any link on the web that contains this site, don't ever click it. Remember that this is dangerous and may lead your PC to the status of being brutally infected.
If you do believe that your Adobe Flash Player is outdated - it's a good idea to get the update at the official site, instead of obeying this fake pop-up window, which is obviously a scam. Finally, if you've see this fake pop-up in your browser it's a good idea for you to scan your PC with a reliable security software.