I have one main domain for this sector and, a couple of years ago, I bought several domain names with the main keyword in them. Let's say my main domain is widgetworld dot com and the other domains are largewidgets dot com, redwidgets dot com and so on.
I did have plans to build relevant sites with them, but this is unlikely to happen for the foreseeable future. But I still want to hang on to them. My question is, what do I do with them - apart from develop them, which is not a factor right now.
I don't want to park or 301 redirect them to the main domain, as I want to keep their identity/brand independent - at least for the moment.
If I simply put a single holding page with some keyword relevant explanatory text on there, are there any SEO issues for each of them (or even for the main domain)? The main domain sits on a separate server, but these other domains all sit on the same reseller account server. However, my company is registered as the owner of them all and if I, for example, stick adsense for domains on them, it would be clear that there is a connnection between them and the main domain.
If I simply put a single holding page with some keyword relevant explanatory text on there, are there any SEO issues for each of them (or even for the main domain)?
No problem, just ensure that the content is unique and relevant to the keyword domain.
There is a big upside to doing this too. When you actually get around to developing the site it will already have "age" on its side and will rise in the SERPs much faster than either a 301'd or a new site.
There's also no problem with them all having the same registered name and being on the same server, in fact when I do this I actually link the sites together.
My main concern was of negative effects on the 'main domain'
Personally I have experienced no problems and 95% of my domains are all concerning the same global widget subject plus I am using many different TLD extensions besides .com such as .cn .in .co.uk .eu .asia .mobi .biz .etc :-)