OK here is an update:
The download speed when watching directly on youtube is variant (maybe depending on peak times either on my shared connection or on youtube) while it seems to be at full speed (60 - 62 KBps) when using a download accelerator. I do get full speeds on youtube but less frequently than using a download accelerator, it is weird. If it were a problem of the _local_ network being overloaded because of many users, then why would the download accelerator still work at full capacity. Still trying to figure it out.
ZeRaW wroteAre you using GigaGet in accelerated mode.
I am not sure what that is since there is no setting for it _that I could find.
GigaGet is downloading from only one source (youtube), now internally what it is doing exactly (like how many connections to youtube is it opening concurrently) I am not sure.
@ali: I meant by streaming the way rahmu describes it