Does subdomain hurt SEO on main site

[katandmouse]

This client sells event management software and puts all their clients on different subdomains of their main domain. Looking in SEO tools like OSE, when I run a backlink analysis, it pulls up all the backlinks to the subdomains as well as those for the main domain. In webmaster tools when I look at queries, impressions and clicks, they get at least 30 times more traffic and impressions on keywords found in their subdomains and very few on their own.

In other words, all these tools are providing a collective analysis of main domain and all subdomains. All the backlinks and keywords recorded for those subdomains are not at all relevent to the keywords they want to rank for. For example, their software supports Boy Scouts, so keywords they rank for according to WT include merit badge, scout camp, etc., but of course, that's on the subdomain. As a result, if you were to take a snapshot of their online presence as these tools do, you would think they were a boy scout website and not a software developer if you include the subdomain, along with its PR, backlinks, keywords, etc.

So the question I have is, does Google connect all these subdomains with the main domain and then water down the main site with irrelevant keywords, content and backlinks? Or does Google see all those subdomains as completely separate and we don't need to worry or move their clients off their subdomain? I'm worried about Google assigning a "boy scout" relevancy to them. Am I wrong?  What would you do?

[AlanBleiweiss]

It happens all too often when site owners take a path they or someone advising them thinks makes sense at the time. Until it goes bad. Then it just becomes a beast...

[katandmouse]

Thanks, Alan. You confirmed what I thought. Huge problem for them to clean this up, but I don't see anyway around it.

[AlanBleiweiss]

Without seeing the site and example subdomains I can only speak from experience with other sites that have similar problems.

While a subdomain is "technically" a separate site from Google's perspective, one factor that can change that is interlinking - how interwoven are the subdomains to the main site from a linking perspective? If interlinking is heavy, this clouds the "stand-alone" site notion.

However, even then, what is the status of analytics and webmaster tools account assignments?  Are all the subdomains tracking with the same account IDs as the main site?  If so, it would be important to split them out.

Ultimately, the PROPER, best practice recommendation regardless of any of that, would be to have those subdomains migrated to an entirely different root domain.  The topical focus is radically different.

The bottom line factor is that subdomains DO impact a main domain because they are subordinate to that root domain.