well, I'd be inclined to disagree with you on that being bad advice - when it comes to the invisible text end of things - I was not referring to coloured text that is the same colour as the background - that has long since been overused and is definitely ignored by engines now. The days of driving traffic to your site by embedding numerous 4 letter explicit words in colour in the background of your site is long gone. I was referring to the metadata that is invisible to the viewer of the page. (I had no idea if the term metadata would be over the head of the original poster)
As to metadata no longer being read by web crawlers, I completely disagree on that one 61dynamic.... it is a starting point for any site optimization project. If you Google 'web site optimization' you will see that everyone and their uncle has an opinion on it and is offering the perfect way to do your site to get the maximum number of hits. Lots of them are a lot of crap and just use plain simple logic and overuse of keywords in the body text of your site and use automated engines to resubmit your url over and over again to useless search engines... trust me on this one, a lot of those sites are like snake oil salesman.
Quite frankly, the best way to market your site isn't through a search engine like Google... it's through word of mouth, through good old tried and true direct marketing - either snail mail or purchasing quality mailing lists and sending tightly targeted html email and by joining nationally recognized associations that offer online galleries that are targeted at the people who are looking for the work you produce. Sure, you can get traffic coming to you through search engines, but I for one would not want to rely on that as my only method of marketing. In the end it really ends up what you're trying to do, and who you're trying to sell to. I know many nationally recognized and top level professional shooters who don't rely on their site for business generation... it's a tool that get's people to see their work... they use traditional methods for the bulk of their initial contact with new clientele and it works... and as a purchaser of photography (I'm a creative director/designer for a living - as well as a shooter when time allows) that's what I rely on...