Subdomain of redirected/unused domain

[stavros]

We have an alpha site which is very different from the beta site we plan to launch in a few months. On 5th July we briefly launched the alpha site on our intended domain for the beta site (example.com) but quickly (on 16th July) decided we would move the alpha site and put up a holding page on the main domain example.com so that users are not confused when we launch our rather different beta site there.
Given that the alpha site is geo-specific, we felt the best location for it would be example.co.uk, but, because we want to eventually redirect users typing in example.co.uk to example.com, we put the alpha site on a subdomain: sub.example.co.uk.
Initially we saw organic traffic gradually increasing, especially after submitting a sitemap. However, since 12th August our organic traffic has dropped to almost nothing (~2 visits per day). This is despite having over 100,000 pages indexed. 12th August coincided with a request from webmaster tools to re-verify example.com.
Summary:
So, to summarise, we have a site on a subdomain whose main domain homepage (only) is redirected to another domain. Is there a reason why the subdomain pages will not rank, despite lots of pages being indexed? Would we improve our rankings and traffic by moving the alpha site to a completely different domain rather than using a subdomain? Is there a requirement for a main domain homepage to be an integrated content page in order for its subdomains to rank? Or could there be another reason for our lack of organic traffic?

Any thoughts greatly appreciated.

[tedster]

Hello stavros, and welcome to the forums.

Would we improve our rankings and traffic by moving the alpha site to a completely different domain rather than using a subdomain?

That's a very real possibility.

Is there a requirement for a main domain homepage to be an integrated content page in order for its subdomains to rank?

Not that I'm aware of - but I've also never seen a situation such you described. It could be such an "edge case" that Google kind of chokes on it.

Or could there be another reason for our lack of organic traffic?

Without an in-depth audit of the site it's hard to say much, but this is always a possibility. Have you ever played with any kind of link-building "schemes"?

All this moving things around only happened since July 16 and it's a new website. I'm pretty sure that all those changes made the Google algo "suspicious" enough not to rank you early on. And even after you get things stable, it will probably take several months to see a lot of traffic.

[stavros]

Hi tedster, thanks for your response. Good to get your opinion. We certainly haven't been involved in any link-building schemes, so I don't think we've been penalised. In fact, since we put some content on the main domain homepage with a link to the subdomain, or organic traffic has begun to increase again gradually. I suspect the issue was that the main domain had no content at all, which was preventing Google assigning any kind of domain authority.

Now that the organic traffic is increasing, we need to decide whether to move the site to a different domain so that it can be a main domain rather than a subdomain.

Do you think Google assigns more authority to main domains than subdomains generally, or does it make no difference?

[tedster]

I've never seriously studied or tested that question - and it's a good question. My first guess (and it is a guess) would be that there's no automatic factor here - that well backlinked content has no disadvantage on a subdomain.

However, I do think you're onto something with the idea that a subdomain with no content on the main domain could have a struggle. If so, this would not be an intentional thing at all, but an unplanned technical side effect.

[stavros]

Thanks again for your thoughts