Page last updated at 23:44 GMT, Friday, 2 May 2008 00:44 UK Spam - the scourge of every e-mail inbox - celebrates its 30th anniversary this weekend. The first recognisable e-mail marketing message was sent on 3 May, 1978 to 400 people on behalf of DEC - a now-defunct computer-maker. The message was sent via Arpanet - the internet's forerunner - and won its sender much criticism from recipients. Th