SEO by using two diff webspaces

If a site is heavily linked out of context, the web site that is linking (probably your ISP hosted site) may get penalized. When linking, a few points may be useful keep in mind:

1. That the linking is appropriate within the context
2. Avoid duplicate content
3. Avoid cross-linking (linking between both the sites) for the purpose of increasing the SERPs.
4. As was mentioned by Sapien, it important to get valuable links thank the ones that are not rated or indexed by search engines.