I have an old domain which I stopped using for a while, it was an ecommerce site selling gifts/gadgets which I gave up on and just put up a holding page saying "New shop coming soon" on the root domain and deleted all other pages on the website. Having checked it recently it still has page authority of 44 and domain authority of 33 on the root domain using SEOMoz tool bar. Have around 180 root domains pointing to it. Now I am creating a new website with a completely different niche, although it can be related to gadgets. My question is it worth using a 301 on the root of the old domain and point it to the new domain and let Google know through webmaster tools? Or should I just start from scratch again? The anchor text keywords used for the old domain/website will not relate to the new domain/website. It would be nice though to get someone else's take on this. I did spend quite a lot on SEO on the old website so hopefully it can come to some use.
i would use it as a redirection anyway, i would also check the the type of sites linking to it if they are not completely different niche.
Hmm I think that the redirection will be of no significant benefit if you will be focusing on conversions for they are in a totally different niche, however if you're after the traffic and perhaps you have affiliate links on the new site the redirection is worth giving a try.