I wanted to change the format of our larger site which would include removing the shared borders.
If I took the old border content and placed it into an includes file instead, would the search engine see it the same as it did the shared border? Is it basically the same thing? Do I need to publish through Frontpage to make and Include file work?
Sorry so many questions at once, the site is very well indexed and I hate being so paranoid about losing ranking by changing the format :)
For your purposes, yeah, the included pages will work the same and look the same to the SE spiders.
As for publishing, you don't need to do it through FP, but it will make things much easier in the long run. If you make a change to, say, only the bottom footer include, the FP publishing routine will only transfer that file to the remote server, then update all affected files on the server. If you used FTP you would have to transfer every affected file.