Very weird this. When MissingSync is running, my Internet connection will slow down to 2kBs, when it is not running I can download at 370kBs (tested with OpenOffice). It is the same for anything elese from the web.
I seem to be having the same problem with Romeo, after I disconnect my phone, although I'm not sure that's what's doing it yet. I'll post back when I check it out further....