'spaw - I agree; it is one of my pet peeves as well; but sometimes it is a poorly expressed response to a particular comment; sometimes it is just that a particular part of the thread hits someones attention.

and sometimes it is just a person coming along and not reading - I've seen the SAME link posted at about 1 to two hour intervals several times. within minutes is understandable - several hours later is laxity. (usually)