Do you know what - I think I've found the answer, by George!!!
I'd pasted it into my iblog.com page to copy and paste it into my sig - and I'd noticed that when the zwinky had disappeared, that iblog was having one of it's frequent tea-breaks - I couldn't get on to it.
Just now I saw my norty lil zwinky had come back - and lo and behold, iblog is back online!!!!!
Can that be the case?? That it retains it's link with it's home - as it were - and shuts down when iblog does????
How rude of it! lol
Thanks anyway, Pierce!