I have a vbulletin forum, running without the vbSEO plugin. Can I install vbseo now, or is this something that should have been done from the start? And what will happen to previous posts?
You can install vbSEO without any risk. If you have any doubt, you can ask vbseo forum, they are great supporters.
Agreed - there's a comprehensive readme offering a walkthrough to the installationm, and the forum to fall back on should you get stuck
When creating a new forum, we recommend you install vBSEO right from the beginning. However our 301 redirect system ensures that you can (and should) install vBSEO at any stage of your forum life, in order to get your SEO advantage.
is VBSEO give free updates forever once you buy it? and other than writing URLS and making them static html, is there any other seo benefits/?
Your vBSEO license is a lifetime license. There are is an annual $35 free for access to upgrades. vBSEO is a complete SEO solution for vBulletin. It has hundreds of features and configurations. You can view a demo here: http://www.vbseo.com/demo/