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I have a website that is pretty popular with good SEO rankings. Part of the site is ran with Wordpress (homepage, articles and static content pages), another part is the forums using vBulletin (probably 75-80% of the pages on the site) and I also have a directory using another software. I have a new website and was going to add a link to it on my older site on the sidebar of Wordpress across all the Wordpress pages. Should I stay away from that or just put it on the homepage? The text is basically "Come check out the new {keyword} site at {SiteTitle}, by the founders of {OldSiteTitle}. I would have the keyword and sitetitle linked over to the new site. Would I be hurting either site by doing this or should it be looked at as a natural link as I do own both of the sites and want to let people know about the new site.

I'm trying to get my server PCI Compliant and they want me to switch the forums at http://www.usacarry.com/forums/ over to https because of the logins. Could this possibly affect my existing rankings?