Since the very beginning of Wikipedia, the parser has contained a special pattern for the letters ISBN followed by 10 (now 10 or 13) digits, resulting in a link pertaining to the specified International Standard Book Number. MediaWiki inherited this behaviour from UseModWiki. At one point, a Special:Booksource page was introduced as an intermediary between the ISBN mentioned in an article and a list of alternative libraries and bookstores. Since June 2003, the Special:Booksource page transcludes user-editable contents from [[Wikipedia:Book sources]] and substitutes the word MAGICNUMBER.
Today, new numbering and reference schemes are not introduced in the parser, but instead through templates. If the above had been invented today, we would write {{ISBN | 9876543210}} instead of the "naked" pattern ISBN 9876543210.
For many years now, it has been asked if we could have ISSN support similar to the ISBN support. ISSN are International Standard Serial Numbers, identifying newspapers and journals (collectively called "serials" by librarians), such as Nature (ISSN 0028-0836) and Science (ISSN 0036-8075).
An increasing number of Wikipedias have introduced the template {{ISSN|0028-0836}} but the template designer then has to decide whether this should link to http://dispatch.opac.ddb.de/DB=1.1/LNG=EN/CMD?ACT=SRCHA&IKT=8&TRM=00... (as in the English Wikipedia) or to http://worldcat.org/issn/0028-0836 (as in the Danish Wikipedia) or to http://libris.kb.se/showrecord.jsp?q=numm:0028-0836 (as in the Swedish Wikipedia) or to http://www.gegnir.is/F/?func=find-a&find_code=ISSN&request=0028-0836 (as in the Icelandic Wikipedia).
The national libraries (gegnir.is, kb.se) are very useful for one country's local serials, but the international ones (worldcat.org) are more useful for internationally renowned journals.
It would be a lot easier for the template designer, if the existing template (without modifying the wiki parser!) could link to an intermediary page called Special:Serialsource which could transclude text from a user-editable [[Wikipedia:Serial sources]].
Is this something we could hope to see implemented?
It is important to note that other numbering schemes such as ASIN (Amazon), LCCN (Library of Congress), OCLC and DOI are tied to one supplier, and there is no need to link to different sources. ISBN and ISSN (and perhaps other schemes?) are different.