Building a product clients will integrate into their sites: What is the best way to utilize my clients' unique domain names?

[emzeegee]

I'm designing a hosted product my clients will integrate into their websites, their end users would access it via my clients' customer-facing websites.  It is a product my clients pay for which provides a service to their end users, who would have to login to my product via a link provided by my clients.

Most clients would choose to incorporate this link prominently on their home page and site nav.
All clients will be in the same vertical market, so their sites will be keyword rich and related to my site.
Many may even be .org and ,edus

The way I see it, there are three main ways I could set this up within the product.  
I want to know which is most beneficial, or if I'm missing anything.

1: They set up a subdomain at their domain that serves content from my domain product.theirdomain.com would render content from mydomain.com's database.
product.theirdomain.com could have footer and/or other no-follow links to mydomain.com with target keywords

The risk I see here is having hundreds of sites with the same target keyword linking back to my domain.
This may be the worst option, as I'm not sure about if the nofollow will help, because I know Google considers this kind of link to be a link scheme: https://support.google.com/webmasters/answer/66356?hl=en

2: They link to a subdomain on mydomain.com from their nav/site
Their nav would include an actual link to product.mydomain.com/theircompanyname
Each client would have a different "theircompanyname" link.
They would decide and/or create their link method (graphic, presence of alt tag, text, what text, etc).  
I would have no control aside from requiring them to link to that url on my server.

3: They link to a subdirectory on mydomain.com from their nav/site
Their nav would include an actual link to mydomain.com/product/theircompanyname
Each client would have a different "theircompanyname" link.
They would decide and/or create their link method (graphic, presence of alt tag, text, what text, etc).  
I would have no control aside from requiring them to link to that url on my server.

In all scenarios, my marketing content would be set up around mydomain.com both as static content and a blog directory, all with SEO attractive url slugs.

I'm leaning towards option 3, but would like input!

[katemorris]

The fact that the links are all related to what you do doesn't change that they would all be coming into the same structure in about the same way from every site. Editorial links are those placed once on a site by the owners without provocation to inform their readers about something they find interesting or useful outside of a planned relationship. Editorial links are chaotic in nature, meaning there is no pattern to them. Google has been working to find and count these links higher than crafted links which typically have a pattern.

I'm not saying this is definitely going to be the case for you, but the more links are designed to appear, the more they have a pattern. You're trying to negate that, but lets just say there has a tendency to still be a pattern. That's why I mentioned not to count on these links. They might do you some good, they might not. I hope that answers your question!

[emzeegee]

This is excellent input.  Thanks!

Option 1 is actually the most complicated from a development standpoint and relies on the clients being able to configure a subdomain and cname correctly.  It is likely the most attractive from a client's point of view (being able to direct people to product.theirdomain.com) and the least attractive from an SEO point of view.

Options 2 and 3 are more or less equal in terms of development and are much easier than option 1.
It is not ideal for clients to point visitors to ourdomain.com/product/theircompanyname, but plenty of third party products do this and our marketplace isn't the most tech-savvy.

One last question. when you say that the links wouldn't be editorial in nature, they would still be heavily contextual.  What exactly do you mean by editorial and how does that differ from contextual.

This isn't like a wordpress template that could be used by any kind of business - 100% of clients would be in the same sector and their keywords would all align around the same general themes.

It is possible that some clients will link to the product from within blog posts or somewhere other than navigation also.

[katemorris]

It sounds like you intend on using this scheme for link development purposes, but I'd warn not to rely on any links created this way. They would not be editorial in nature and therefore you can't count on them in the long term.

That being said, there are two ways to look at this: from your perspective and your client's perspective. The best route in each case in my opinion is:

Yours: #3 by far

Theirs: #1 to keep things on their domain. If I were them, I'd want people staying on my domain.

If you are looking at this from just an SEO perspective, do #3, but if it were me, I'd ask your first set of clients what they prefer and work with them from there.