Randy Windsor, the SEO facilitator with Network Solutions,  said as follows:

There are a few best practices that should be followed to keep from setting off alarms with the engines when you are setting up interlinking.

• It might look suspicious if you have many interlinked sites launched on the same day. So try to do a little at a time when setting the links up. Link out from one on one day and link from that one out to others at different times.
• The web site the interlinked sites point to must have other links from other sites. (If you do not do this, all your sites have same back links.
• Do not link all of your sites to all of your other sites. (This causes issues with reciprocal linking (bringing down the value) of the links and makes the interconnectivity between them stand out.) Remember that one way links are more powerful.
• All of this will work much better if there is relevant information for the visitors of all the linked sites. Be sure they have some interest to share before you create links just for the sake of a link. The engines have the interest of the users in mind.