Clarification regarding a column name

You can simply say them as meta_value, like it store the post ID if meta is for post or store user_id if meta is for user.

AnsPress uses this table for storing many type of data. data types can be defined by apmeta_type. For example, when post vote is stored then post ID is stored in apmeta_actionid. Same happen when post subscriber is saved. BUT when tags or category subscriber is added then term_id is stored in apmeta_actionid.