Mark Lee noted in a private message (but may be persuaded to publish in a blog) that Learning Objects (LOs) and Reputation, Attention and Trust (RAT) would be a good topic for a paper. It seems most of the literature is concerned with educational aspects of LOs such as standards and retrieval and not much on evaluation in a slashdot-like manner.
Slashdot and similar systems depend on the "wisdom of crowds"(WoC)-type evaluation. Whether there is a sufficient number of people interested in LOs with the motivation to evaluate LOs to get the WoC effect is an interesting research question. Do LOs need a high-level of evaluation or would blink evaluation with a lot of people work sufficiently well.