The mystery is solved - why our super duper broadband access sometimes dwindle to such a pathetic crawl that we can't even connect to Yahoo! mail. It so happens that ISP Singtel is at liberty to, and actually does, "throttle" their consumers' broadband speeds to suit their nefarious intents.
The Sydney-based Australian Federation Court has found Singtel-Optus guilty of "deceptive conduct" under the Trade Practices Act. Singtel's ads had offered a monthly plan for download of data during peak and off-peak hours. But if a consumer had exceeded his quota of peak hour usage, his broadband speed during off-peak would slow substantially (the whole service would be slowed to 64 Kbps). This occurs even if the consumer had not used any of his off-peak data quota. Australian Competition and Consumer Commission (ACCS) took them to court for the trickery. The Court ruled that Singtel had failed to sufficiently inform potential consumers their broadband speeds would be throttled back to sub-broadband levels.
Here in Singapore, they don't bother to give you 3 Mbps of promised speed even if you had explictly signed up for it. And who is there to stop them from siphoning off bandwidth to support their higher priced 10 Mbps customers (who is also conned by the same "up to" qualifier in the ads)? Or feed their resource hungry mioTV service?
The judge noted that in its arguments, Singtel-Optus implied that consumers do not rely on ads and cannot, under those circumstances, be misled by them. Note also the caustic in Justice Nye Perram's remarks, "This proposition sits uncomfortably with the size of the advertising campaign in question, which is clearly substantial and inconsistent with an exercise conducted sheerly for the merriment of its designers."