This thread is dedicated towards coming up with several web-design and web-development "bo bo's" and "no no's"...

Please only post things that can be validated and documented; once a good handful of information has been created this thread will be reposted with all ideas incorporated.

My alltime favorite, the mass usage of subdomains... Search engines are the largest incoming referrals of users (at most large communities anyway); utilizing subdomains is like using a seperate domain for your sections; which will highly impact your search engine rankings.

A site at http://www.undergroundnews.com is NOT the same as a site on http://www.undergroundnews.net, they are seperate domains, additionally using a subdomain for content like forums.undergroundnews.com would be the same as using a seperate domain in accordance with search engines.

So, if you have an active forum with a ton of content for spiders to eat up, whichever domain the forum is hosted on will be accredited with the se bonus as the forum is hosted on that domain.

This means if you have say 200k links to your forum, and 50k links to your site, it'll vary what your SE ranking is depending on the domain used (may it be http://www.mysite.com or forums.mysite.com).

Broken down with the data from my example with the usage of subdomains:
http://www.mysite.com 50k
forum.mysite.com 200k

Broken down with the data from my example without using subdomains:
http://www.mysite.com 250k (with both sets of data combined).

A lot of sites utilize subdomains for organization, however they are unwittingly cheating themselves out of valuable rankings to their site.

I will be posting a little something on FLASH ONLY sites, mainly a rant on no crawlable content for spiders and text readers (mainly non-hi-fi versions); this should be done in a couple of nights.

Also still taking sugguestions