I experience slowdowns from time to time. Often they occur around 5 pm or on holidays when traffic can be expected to be higher than usual.
I do not believe that it is due solely to Yahoo BB. The Internet does get hugely busy on occasion.
I have no idea about Firefox since I prefer not to use it. Safari allows me to open multiple windows, but I have never been able to do that with Firefox. Once in a rare while I watch a seminar that can only be accessed via Firefox. Beyond that, I do not even think about it.
Norm
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Firefox certainly can open multiple windows, in several different ways. You can move tabs from one window to another, and even open a tab in a new window.
Yes, slowdowns do occur, but I have never seen anything like this before. Parts of pages open up, others don't; pages open without the usual formatting. Sometimes I get 'cannot contact server' on multiple tabs, then 5 minutes later everything opens normally. I'm wondering if the latest typhoon might have caused infrastructure damage somewhere. Another odd thing is that running Miro to download torrents will sometimes prevent both Firefox and iTunes from connecting at all, which is definitely a new occurrence.