How an Algorithm could be called an online algorithm?
To some degree it means use fresh data,but what is the diference between online and offline?
It is some kind of automatic,so the ability to control it is critical import.
Till now we could see two kind of cycle,the first one is for get a parametar,the second one is for get a parametar could change with time and fresh data set.So as for a online algorithm we just could think about the parameter as the function of time is just Ok.
We need to consider the gap of time or maybe this time might as the funciton of  the amount of dataset either,or some other conditions like showed in Paxos is some other machine`s condition.