The bugs are biting today!
This is not a virus / malware kind of bug. This is simply a malfunction and it will be fixed at some point in the near future.
On nearly all client computers, I have installed AdBlock Plus in your browsers. This is known as a “browser extension”. It blocks all but the most benign ads. Text based ads (such as the ones Google typically employs) are allowed. Blocking ads is an intensely debated issue. Most of the websites we use provide their content to us for free, so shouldn’t we allow them to advertise? In theory — yes! However, many websites use a 3rd party to serve up ads. Misleading ads have directly or indirectly caused malware infections for my clients — necessitating 5 to 6 hour jobs to restore a computer. This is why I employ AdBlock Plus. It works just as well with Chrome also and I have put it in your Chrome browsers.
End of lesson. Now its time for some bad news. There is a flaw in the interoperability between Adblock Plus and the latest version of Firefox. (Reading – http://www.pcworld.com/article/2156401/mozilla-adblock-bug-can-dramatically-boost-memory-usage.html#tk.rss_all). It will be fixed, but your Firefox could get REALLY slow. If you are noticing problems, I am going to ask you to do one of 2 things. This may not need to be a permanent change, so long as AdBlock Plus and Firefox resolve the issue.
1. Use Google Chrome. If you are a Mac Firefox user, you could also use Safari.
2. Keep using Firefox but (temporarily) disable AdBlock Plus. You would do this from the Tools menu, Add Ons, Extensions —> simply click on the disable button for AdBlock Plus
**Ad Block Plus for Chrome is not affected by this). If you want to block ads in Safari — I recommend this extension. https://getadblock.com/ AdBlock and AdBlock Plus are offerings from different companies.
And finally if you want to read about AdBlock Plus, https://adblockplus.org/