What should I think about these unique certificate serial numbers I  was looking at the serial numbers of the certificates for www.google.com and wordpress.com.  Wordpress was listed by openssl as:

04:0B:D4:F8:25:88:C5

This serial is listed as the serial for both my specific wordpress.com domain and for www.wordpress.com.  A google search using the serial number as a keyword shows only my wordpress.com domain (because I pasted the serial number into one of my pages) in the results.  I would expect to find  other hits on Google.

The site www.google.com was listed by openssl as:

5F:BB:FC:7C:4C:6E:FF:92

That serial number, in a google search, showed up with only two listings, mine (Because I again pasted the serial number into a page) and cryptostorm.org.

I would think these numbers would have been put on the google search engine, and yield (probably) many hits.

@cpast:  I'm not downvoting your answer, but I need a better one.  I can see that google indexes the serial numbers and that is obvious if you type or copy the serials I've provided (above) into the google search bar. Using fingerprints as a search term, I can normally see many items in a search result.

And - I know people often cut and paste whole certificate info pages from Firefox, and put them into forum posts, where they ask "What's this?" or "Why's this?"

Additionally, the statement that nobody cares seems silly. One of the first items in the certificate is the serial, and certificate revocation lists are indexed by certificate serial numbers. Those serial numbers are very important.  Your answer seems trollish.  Anyone else?

@SOJPM: Serial numbers are unique within a CA.  This serial number (e.g. Wordpress) - is supposedly used by hundreds of thousands of Wordpress associated domains.  It should have google indexed data associated with it. Unless I have a "special" one.

@cygnusv: No offense taken.

@all: Why can I edit cpast's comment? I'm new to stackexchange.  Seems odd.

@SOJPM: Thanks, and yes that's what I meant.

@truthserum:  Here's the expiry:

issued  on            : 2014-04-14 18:09:05
  expires on            : 2015-10-14 11:29:26

So, it's been around awhile (if what I see is valid) and should have been the cert for a lot (millions?) of users.  I'm not sure how many users WP has. 

Maybe someone else can dump the cert or look at the Firefox Cert GUI - and see if the serials match what I have?
I would think these numbers would have been put on the google search engine, and yield (probably) many hits.


This assumption is wrong. Certificate serial numbers are not indexed by common search engines, nor are they typically posted to any HTML site. Frankly, I'm not sure why you would assume they'd be indexed.

The Wordpress certificate is used for all Wordpress domains; it is for *.wordpress.com (matching all subdomains of wordpress.com), and has wordpress.com as an alternate name (so it also works there). The Google certificate you list is only used for www.google.com; it is again something that commonly shows up (Chrome reports a different certificate for some reason).

The reason you don't find any posts about them on Google is that no one really cares.