Well I was anyway when I noticed it on todays SE1 newsletter.
I know the British Library collects all ISBN's.
[ SE1 Direct ] Issue 532
Monday 17 January 2011 ISSN 1750-0656
ISSN (International Standard Serial Number).
The ISSN is the standardized international code which allows the identification of any serial publication, including electronic serials, independently of its country of publication, of its language or alphabet, of its frequency, medium, etc. The ISSN number,therefore, preceded by these letters, and appears as two groups of four digits, separated by a hyphen , has no signification in itself and does not contain in itself any information referring to the origin or contents of the publication.