That niftly little "last updated" indicator
Oh all this could be solved by just a simple little line of text that says the date of the last day you updated the page. That way, if someone comes onto your ex-page they can just say "Oh! Last updated December '96? Guess I'll just be looking" and the clouds would part and the sun would shine and- um yeah...
Quick Tip
The most convinient spot for you to place a "last updated" is on your main index right bellow the tittle of your page.
Closing down your page
If worse comes to worse you can always take your page offline when you loose interest in it. I prefer leaving up the information that was there myself. But then if you are paying for your webspace (which I think is kind of silly) then it would be polite to shut down the rest of your page exept a simple goodbye note on your index. Leave it up long enough so that people can see your gone and why.