I face a rather common problem of displaying a list of nodes similar to current one. Similar node is defined as one having at least one taxonomy term that current node has. There are few solutions available as modules, however most modules I've found are in beta stage for Drupal 7.
I've also found a couple of solutions based on Views and contextual filters (such as http://scito.ch/content/show-related-nodes-block-based-taxonomy-terms-views-3-and-drupal-7) or relations. I quite like this way as it saves me installing extra modules and with Views being actively developed and supported I'd prefer to use them rather than any custom solution. The problem I can't get around is how to sort "similar nodes" by the number of terms they share. For example, if I have "IPhone 4S" Node with Terms "Gadget", "Apple", and "Phone", I want similar nodes in the following order:
- IPhone 3 (Apple, Gadget, Phone)
- IPad (Apple, Gadget, Tablet)
- Mac (Apple, Computer)
- Bramley (Apple, Fruit, Tree)
How can I sort nodes in this view by the number of terms they share?