Advice would be much appreciated : knowing nothing much about "web presence" such as Google, Facebook, etc. though familiar with Serif Web plus software, I would like some views on the best one to use for publishing a Christian web site with responses from other people of (any) faith, similar to the site I am on now. (not WordPress)
Any members with a good experience?

First Serif is a WEB authoring tool. Its purpose is to create WEB pages that can then be uploaded to a WEB server. Google is a search engine that helps people find sites that pertain to what they are looking for. Facebook is a social media site where people can share their lives. So Google doesn't apply, Facebook might be appropriate if you just want a wall to post comments and Serif would be used if you want to design your own site.

It sounds like you are looking to create a discussion site for Christians. There are several forum softwares that you can use to create such a site. Your first step would be getting a domain name and a web host service. From there you can design your site. You might want to look for a host service that offers discussion type forums.

Another alternative is creating a Yahoo group (or similar).

I think the OP was asking about total web presence. Search Engine Optimization, Networking (Facebook, Twitter,)

I don't know much about software, but read the October Issue of the Anderson Agency Report about comple SEO. It's a very nice article.

Thanks ScottGem & ITStudent ~ have got Domain Name already & advices appreciated ~ think I am a bit daunted by the technicalities of the forum bit, so 'forum software' is a good idea I shall look into as well as 'Yahoo Group' or similar. Thanks again