User talk:Johnhallcrest

Please do not add inappropriate external links to Wikipedia, as you did to Thermochromism. Wikipedia is not a collection of links, nor should it be used for advertising or promotion. Inappropriate links include (but are not limited to) links to personal web sites, links to web sites with which you are affiliated, and links that attract visitors to a web site or promote a product. See the external links guideline and spam guideline for further explanations. Because Wikipedia uses the nofollow attribute value, its external links are disregarded by most search engines. If you feel the link should be added to the article, please discuss it on the article's talk page rather than re-adding it. Thank you. Materialscientist (talk) 22:36, 13 July 2010 (UTC)