Might be worth investigating the health of the server's network connection if enough people are having these issues.
That is, it might be packet loss from the server's ISP, not yours.
How to test for packet loss
Open a command window (on Windows 7, just hit start and type "cmd" in the search box and it'll come up)
Type:
ping -t google.com
Let it run for at least 10 minutes. (You can also let it run overnight, while at work, etc. Doesn't hurt anything.) Hit ctrl-C to stop it and see a summary of statistics.
What you want to see is 0% loss. It's okay if it says like "Received = 5000, Lost = 2 (0% loss)". That's pretty normal. 1% is worrisome. Over 5% will make most games completely unplayable, though you might not notice it in browsing or downloading.
If you know the server's address you might be able to ping it directly (some servers block pings) and check the results that way, but pinging a neutral site like Google will help you determine if it's your connection.
If the ping test shows noticeable packet loss then:
#1 cause of packet loss is probably routers. Unplug your router for 15 seconds and plug it back in.
#2 cause of packet loss is probably your DSL/cable modem. Sometimes they just go bad and need to be replaced.
#3 cause of packet loss is usually something bad with your internet connection in general. If you're using cable or DSL, call support and tell them you are having packet loss problems (5 years ago you might as well have been speaking Babylonian but these days they seem to understand the concept of packet loss = poor connection quality = something that can be and must be fixed). You could also try taking some of your cable splitters out of the loop and that sort of thing, though I can't say I've ever had luck with that.