We own a lot of generic UK domains, many dropped by former site owners so have worthwhile links.
For many of these we have built minisites (e.g 5 or so pages of decent quality content). The sites generally rank for one or two keywords and have some modest traffic - e.g. 20 visitors per day. To be blunt, we have then used some of the sites to sell ads / links - obviously for SEO benefit. Some sites have taken off and we have developed them out more fully. This has worked quite well.
There is a limit to the number of sites we can manage ourselves so just wondering, if there is a market out there for potential purchasers of minisites which are built in this way.