Maybe not. Someone commented at the end of the article that step 5 was wrong - i.e. backwards actually, not sure if true, but if so - that would explain why MySQL won't start properly. It might be nothing, but I noticed so worth checking out.
Regardless, it's time to check the error log and see what mysqld generated during startup, then post that here or Google search for advice and go from there.
The log can be found via "locate mysql.error.log" - once you find it, look for startup errors. If nothing found, you can use mysqlbinlog to read the binary log files in /usr/local/mysql/data/ (in my installation not all were binary). But most importantly, some errors are simply directed to stderr so you may want to check /var/log/system.log as well, i.e. "cat /var/log/system.log | grep -i 'mysql'"