how to store metadata/annotations that are potentially needed for every single page?

i am looking for the best / most efficient way to store counts of the amount of times individual pages are shared on other sites. i can already access the data, so i now need to cache the data effectively.

i am unclear currently on whether to create a new table to store the data - or whether elgg already has some mechanism that can handle this type of requirement. as far as i know, the metadata/annotations can only be stored against entities - and some pages are not attached to specific entities, so some extra way is needed to store/access the count data. how would you resolve this? create a new table (that may potentially have a unique row for every page on the site)? or maybe look to memcache somehow?