Forum Moderators: travelin cat
I use two Validators when a web page is finished -- W3C and Elsop's HTML checker (the later is to verify all links are working--it pickes up broken code that W3C misses, believe it or not!--ignore the javascript errors)
I check Keyword density of web pages with Submit Express' Keyword Density tool to see where I need to change the text (sometimes multiple occurances of things like "click here to view larger image" need to be removed or they will rank highest in keyword density.)
I use Digital Point's Keyword Tracker a lot to monitor my rank in Google for major keywords. It also has a backlink monitor.
I also use PHP Live Support to monitor Page Rank, not only for main pages of one of my sites but also to monitor rank of backlinks.
My main tool for SEO however is using a good site meter that provides referral links. I check this often for new sites to see if I need to tweak the keywords to get a better rank and will sometimes get new ideas for new keywords that produce better results. I can usually raise the rank for a keyword by checking to see what competitors are doing.
Lori