They can pass the year threshold. I have supplementals from February 2004.
The interesting thing to me is how Google ranks them.
I had a development site set up in late 2003 on temporary webspace (subdomain) that got spidered and listed by mistake. So I had a robots exclusion file added on 31st Dec 03 (excluding all robots).
Pages from before end of 2003 (Oct 03) were appearing as full listings and supplimental 2 weeks ago. Subdomain was killed early 2004.
I have pages that have been supplemental for that sort of timescale.
The pages show an email address in the snippet, one that we really do not want promoted and which was removed from the real page a very long time ago. Google has re-cached the pages many times, but still the email address shows in the snippet.
Just to recap. The email address in NOT on the real page. The email address is NOT in the Google cache. The email address shows in the snippet.
Another site (a development server) has been supplemental for well over a year, possibly nearly two years by now. The site was changed to being password protected about a year ago: to stop it being indexed, to stop people reading out of date information there, and to protect the PR and linking of the main site. Google still shows these supplemental pages cached from a year ago, and still keeps them in the results.
The Google URL removal tool cannot remove the pages, as the URL does not pass the criteria of either a disallow in the robots.txt file, or a disallow in a meta tag, or page not existing at all. The pages return a status of 403, but Google doesn't accept that as a criteria for delisting.
I've supplimental results of the pages which were deleted alsmot 2 years back! GOOGLE ARCHIVES!
In desperation, an email to Google got the old snippet (the one containing the email address) deleted within just a few hours.
The page still shows in search results where it should not. It still has the original title, but now has no snippet at all.
I am told that a new snippet will be generated within a few weeks, and after that time that the page will then only appear for searches on the "new" content.
Interesting g1smd - perhaps a sign of a pending large update.
I commented in another thread that I have had pages that were supplemental recenlty crawled which have not appeared in the index yet.
Is it purely a time factor for when pages become supplemental?
I also have pages going back to last march.
Moved a folder from a domain, to it's own domain Jan 2004. Used the Google URL Removal tool. The index page disappeared in 2 months. Most of the other URLS disappeared by Sept.
Just checked the stats today, 1 year and 2 months later, and I still have 404's for some pages, but mostly "long gone" images are getting pulled up.
Emailed Google, and they said, "As long as other sites are linking to you, there's nothing we can do." We tried contacting these websites with the old links, and their email doesn't work, and they haven't maintained their website since they built it in 1998.
>> Just to recap. The email address in NOT on the real page. The email address is NOT in the Google cache. The email address shows in the snippet. <<
OK. For one site, someone at Google recently deleted the snippet as I said above. Another friend has exactly the same problem, and contacted Google by the exact same route, asked the same question and was told that Google "does not manually alter snippets".
But, wait, hang on, they did delete one just a few days ago. Not everyone at Google is singing off the same hymn sheet methinks.
Now here's another funny thing. Someone else with exactly the same problem (I know about a dozen people with this problem on their own or on other sites) contacted Google yesterday, and was told that the snippet is up to date for their page, and the cache is also using content from just the day before (and was shown a search query to confirm that).
I have looked at it, and for all search terms the cache is up to date. However, for some search terms the snippet is up to date and the result looks normal, but for other search terms (including those that contain words from the email address that no longer resides on the real page or in the Google cache) the snippet is one from two years ago, and the result is marked as a Supplemental Result. So, a page can be a supplemental result for some search terms, but not necessarily all search terms, and it also then appears that Google has a separate snippet database that it uses when the result is a Supplemental Result; and that that information is NOT updated even if the real-site page content changes, and is still not updated even if the Google cache is updated.
Second supplemental results are common in the format of
site.com/directory/ normal cache
site.com/directory supplemental listing
The cache is the same on both, and is up to date.
It is the snippet of one of them that is years old.