If you have multiple websites, you can cross-link your websites but make sure these sites have related content.
Also, you should avoid cross-linking a large number of sites as that might send a wrong signal to the search engines.
Should Your Cross-Link Your Own Websites
25 jan 2010
If you have multiple websites, you can cross-link your websites but make sure these sites have related content. Also, you should avoid cross-linking a large number of sites as that might send a wrong signal to the search engines.