If you are on a cable connection (Time Warner / RoadRunner / Comcast / Etc.) you actually share a cumulative bandwidth over a line attached to a node.  Someone else reaching the limit to engage "Power/Turbo Boost" is going to affect your throughput.  Also, if the rest of your neghborhood is on the internet, its gonna affect YOUR individual throughput.  Take a read through the actual contract you agree to and it will blow your mind what you share and how its shared... not to mention the ACTUAL speeds they are promising for a constant measure.

If you know what your doing you can force them to refund 6 months of a years fees, as they know they are not providing what they claim (minus the ToS for their service).  I did, but it took going past regualr support and contacting things like "Office Of The President" and also faxing into EVERY corporate # I could find.  But, I got a check, when I was with TWC, for $216 which was 50% of what Id paid over the year.  They will try to talk you into leaving them upon this, but you are NOT obligated to leave as the problem lies within their technology, not your INDIVIDUAL usage.

OFF TOPIC - If Anon' REALLY wanted to make a real difference in services delivered to consumers, theyd pass this around and make one form of the internet step its game up and start acting right.