A large percentage of questions on Pro Webmasters (approximately 1/4 of the total) are related to SEO issues, so prematurely closing them as duplicates would hamper the opportunity to cover new and additional information, and could stunt activity on the site.
Before flagging a question as a duplicate of another one, see if there are significant differences between them. For example, the question Why isn't my website in Google search results from 2010 is specific to search results appearing in Google's index (not the other search engines), and hasn't ever been tagged with
SEO either (i.e., it's asking about Google's indexing, not necessarily about optimizing content, etc...).
There can be enumerable variations of questions related to SEO issues, so we should be careful not to reduce such a large and active topic here down into a single question. As conveyed by Jeff Atwood (co-founder of Stack Exchange) here and linked to in our Help Center's documentation under
There are similar questions, yes, and so-called “exact” duplicates do
happen, but they are kind of rare in my experience. It’s far more
common to have many subtle variations of a question. I think that’s
OK, because that’s how the world works. Trying to shoehorn a bunch of
semi-related things into one arbitrary container in service of some
Highlander-ish “there can be only one” rule is ultimately harmful.
Remember: while there are aspects of wiki to our system, we
are not Wikipedia. There is not one canonical question about every
possible subject. Rather, there are many.
If questions are exact or near-exact duplicates, marking them as such helps to reduce redundancy on the site. If there are significant differences that might be important to the OP or future visitors however, doing so will limit information on the site, frustrate users, and likely reduce new activity on the site.
Therefore, questions should ideally be flagged and marked as duplicates judiciously, and not just because they seem similar or might be answered in another question. You can always add a comment to a related question instead, like:
See this related question ....