I use it to. Those sites tend to just be link storage areas, ergo no matter where you go the links all lead to the same place. More ergo, no change in speed.
It can be a result of a few other things though: Chinese sites, which host lots, often curb bandwidth to the West during peak Chinese usage time, AND certain ISP's will cut your connection speed at peak times, using some ridiculous loophole called a "fair use policy".