Alt Tags

OK so alot of information you find on the web to do with SEO is antiquated which makes for annoying learning - why don't people put dates on their work? anyway i found this site on using ALT tags, i am unsure as to the value of changing them, but it certainly wont be a negative effect.

I started looking at this because i used this site keyworddensity.com and its helped explain a few things to me, mainly why i've dropped on the tantallon house search...