Many people abuse content curation by simply retweeting worthless content:

In many instances, it is easier to re-tweet something that appears in your newsfeed, even if it’s not that relevant to your industry, than to come up with new material. However, this wastes a valuable opportunity to engage your online stakeholders.

The Canadian Public Relations Society suggests a CIA framework (not not that CIA), but Current, Interesting, & Applicable methodology to decide what content is worth sharing, posting and curating.