Well,on a couple of blogs I have,i'll sort through the keywords and take what I want to use in my meta tags.Blogger is the only blog I know of to use meta tags.But be careful on blogger.If you use to many keywords you will get flagged for keyword spam.Now on google base its simple.Just make your ad on base and at the very bottom just stuff every single keyword in your listing...Works awsome..And if you have great content,you will get even more hits.And also on base I found you get more views by creating your own product type.This way your listing will never expire.Base also has the option to use html.Like they say,post it on base,find it on google.Try it out.