Comment on What is Anchor Text? by Andrew.
The reason for my keenness on this test is that your article is the only one that I have come across that suggests image alt text is (currently) relevant in web search (updated Feb 2012). Back in Dec 2007 Google documented the importance of the alt attribute with relevance to image-search, but makes no suggestion that this is a metric used directly in the standard web search.
Other articles I have read state that the image alt text is not used directly in SEO because of its tendency (in the past) to be used for spamming/keyword stuffing and is therefore unreliable – although this has a detrimental effect on usability/accessibility.
(I state “directly in SEO” since good alt text improves usability/accessibility so could have an indirect affect on SEO.)
Aside: Please show a publish/updated date for the article and comments. In an ever changing world this is an important nugget of information to determine whether it is still relevant or not. I have read through all the comments. Almost to the end (4 comments above this one) Aaron gives a date of November 2009 – this is almost 3 1/2 years ago, which makes me wonder (after spending a not inconsiderable time reading the article and comments) the relevancy of other statements on this page?
Interesting article, thanks.