In our proanarchy society we (and especially we designers) tend to view rules as a collective stifler to our creativity and a hindrance to the overall process.  We think that surly things would be better, easier or more fun if they were done outside the boundaries of some arbitrator handing down of irrational and irrelevant edicts.  Surely we know best.  We view rules as though their sole purpose is to make life, the game or the product worse.  Most of the time that's not a reflection of reality.  Most of the time the rules can (or at least are meant to) make things better.  When it comes to life or games or Search Engine Optimization, we are often better off playing by the rules.

Sports
I have a friend who is a sports fanatic.  He had his own radio show for a while; he announces games; he lives and breathes sports.  He understands very well the concept that the rules enhance the game.  I'm not a sports guy, but I can see the concept being played out here.  I did pickup a few games of volleyball back in high-school.  In any sport there are certain rules and regulations.  All of those rules were established to either protect the players or enhance the game.  They keep the game from being too hard or too easy or too dangerous.  Can you imagine trying to play volleyball outside the boundaries?  It'd be exhausting.  Can you imagine playing Monopoly while allowing steeling?  It would never end.  Can you imagine Catch Phrase where you could say any part of the words to get people to guess the phrase?  It would be no fun.

Laws
If we can ignore the politics of law making for a little while we can see this same principle being played out there too.  Laws are meant to protect citizens and enhance their lives.  Can you imagine a society where it was lawful to steel?  No one would get any sleep!  Even areas that have been abandoned by their government and live "outside the protection of law" still have a law in their hearts that govern their behavior.  Why isn't Steertown, Jamaica the murder capital of the world?  Because they are a law unto themselves.  Laws exist (written or not) and they make life better.  Live this way and reap the benefits; don't live this way and suffer the consequences.

SEO
Laws are meant to enhance our lives.  Rules are meant to enhance the game.  SEO guidelines are meant to enhance websites.  Develop by these standards and reap the benefits; develop by your own standards and suffer the consequences.  The guidelines setup by search engines are not arbitrary.  They take a lot (seemingly everything) into consideration.  They do research.  They preform experiments.  They conduct interviews.  They test algorithms.  They do all of these things to enhance the web experience.  They do all these things so that the people who want to find your website can.

You can develop outside of these boundaries if you want.  There are many who have.  There was was a very cool website called squinterland.com who is no longer in business.  They did EVERYTHING outside the box.  Their entire website was pictures with no alternate or title text.  If you wanted to go somewhere you just had to search for it.  The coolest part about it was that instead of scrolling up and down, it scrolled side to side.  It was unlike any other website I have EVER seen.  But, it didn't work.  They played outside of the boundaries and suffered because of it.  I loved the site, but couldn't use it because it wasn't functional.  In the end, I believe they would have been better served with a less cool website that played by the rules.
Daniel Titus