I do not disagree with the principals you are acting on, but it is important to remember that the internet is not another venue for tract-esque communication. As Steve mentioned, the plan for promoting your church/organization's website depends on the internally identified purpose. Who is your target audience? Is this an information venue for congregants or an "outreach" tool? Does your website content reflect that purpose? Having two distinct websites for those both within your congregation and those who cannot attend, as you have mentioned, makes targeting the content that much easier. And it is your content, more than external links to your site, will benefit legitimate site traffic.

Something that avid web promoters sometimes ignore is the implications of posting links in irrelevant locations. When posting a link, the general idea is that it lends additional information to the ongoing conversation. Offering a link as an example of "This is what we did at our church" in a relevant forum is appropriate and beneficial. Including your church website in your signature on every comment left on various forums, however, quickly becomes irrelevant or obnoxious to readers, depending on the topic of the forum. That will inevitably temper any potential advantages that might result from backlinks. There is a definite distinction between reasonable promotion and spam. 

Which raises an important consideration: services, such as SeoDataService.com, raise rankings, but via questionable means. True, they can be effective, but the theoretical function of these services are to lend false importance to your site by creating irrelevant links to your domain. While this is a popular and accepted activity in many circles, are such attempts to increase the perceived significance of a website appropriate methods for a church? While the results might yield a favorable result (higher search engine rankings, which would presumably mean greater traffic), is this method of generated recognition an ethical means of business? My personal opinion is no, but that is, of course, my opinion. I personally believe that diligent attention to content, effective use of those tools available (such as social networking, professional email, and legitimate backlinking via relevant forums) is the upstanding, legitimate means to produce traffic of consequence and disseminate information that is applicable to users.