9. The system of claim 8 , further comprising the one or more processor-based devices configured to: select the first affinity vector comprising the first plurality of topic affinity level values that are associated with the first user of the computer-implemented system, wherein each of the first plurality of topic affinity level values is of an interest level of the first user with respect to a topic.
10. The system of claim 9 , further comprising the one or more processor-based devices configured to: generate the recommendation for delivery to the first user, wherein the recommendation comprises a computer-implemented object that is selected for the recommendation in accordance with the computer-implemented object having a relatively high automatically determined affinity with at least one topic that is associated with the one or more pairs of contrasting corresponding topic affinity level values.