Do you use a Sitemap Generator for you forum, website or blog? Its a great tool to improve SEO, and helps Search Engines such as Google, Yahoo, and Bing index your site better. Its a very simple step, and its very helpful. Most scripts have a Sitemap Generator plugin if not in the core already. If you have a Sitemap Generator, dont forget to submit it to Google through webmaster tools.
I use of the vBulletin plugins to do it - and I have listed in my google webmaster's account, so my pages get indexed pretty fast.
Ya, and also using sites like Friendfeed to spread your content on the web. I don't rely just on the sitemap.
Of course sitemap is not just the only way. Their are thousands of ways. Just a Sitemap is a very simple but effective method.