I received so much feedback about pages going missing at AltaVista that I thought it best to do a separate article explaining how to know for certain if you've been dropped.
First, AltaVista has instituted results clustering. That means that if you used to have multiple pages appearing in response to a particular search, you will now only have one page displayed. It doesn't mean that your other pages have been dropped. AltaVista has simply selected what it considers to be the "best" one and presented that.
For instance, imagine you had four out of the top ten pages appearing for a search on "stamp collecting." With the new results clustering system, now you will have only one out of the top ten pages. And underneath that listing, you'll see an option to view "More pages from this site." Click on that, and you'll see all the other pages from your site that AltaVista considers relevant for that search.
More experienced webmasters have known to use either the url: or the host: command at AltaVista to see all the pages from their site. For instance, in the past, I could search for:
and see all the pages AltaVista had indexed from Search Engine Watch. If I do the same search now, page clustering still kicks in. As a result, I'm shown what seems to be only one page from my site. In reality, by clicking on the "More pages" option, I can get the full list of 57 pages that have been indexed. It's an extra step, but by doing so, you might discover there's nothing to panic about.
Now let's say you've done a url: or host: search properly and discovered that many or perhaps all your pages really are missing. What happened? Your pages probably were indeed dropped.
What to do? Resubmit. Head to the AltaVista Add URL page and start submitting your key pages. A general rule of thumb is not to do more than five pages per day from any web site. If you have more than this number of really important pages, then spread your submissions out over several days.
Normally, you should see the pages you submit appear within a day or two. The Add URL service hasn't worked that way for the past week or so, but AltaVista says it is supposed to be doing so now or at least within a few days.
AltaVista Add URL page
Checking Your URL
Guide to checking if you are listed at several major search engines.