SOQL - Querying for a list of users the current user is following
List<User> Following = [SELECT Id, Name, SmallPhotoUrl
  FROM User
  WHERE Id IN (
      SELECT ParentId
      FROM EntitySubscription
      WHERE SubscriberId = :UserInfo.getUserId())
    AND Id != :UserInfo.getUserId()
  LIMIT 96];

List<User> Following = [SELECT Id, Name, SmallPhotoUrl
  FROM User
  WHERE Id IN (
      SELECT ParentId
      FROM EntitySubscription
      WHERE SubscriberId = :UserInfo.getUserId()
      LIMIT 1000)
    AND Id != :UserInfo.getUserId()
  LIMIT 96];

List<EntitySubscription> sub = [SELECT ParentId
  FROM EntitySubscription
  WHERE SubscriberId = :UserInfo.getUserId()
  LIMIT 1000];
List<Id> ids = new List<Id>();
for(EntitySubscription s : sub){
    ids.add(s.ParentId);
}
List<User> Following = [SELECT Id, Name, SmallPhotoUrl
  FROM User
  WHERE Id IN (:ids)
    AND Id != :UserInfo.getUserId()
  LIMIT 96];

Invalid bind expression type of LIST<Id> for column of type Id

WHERE Id IN (:ids)

WHERE Id IN :ids

List<EntitySubscription> sub = [SELECT ParentId
  FROM EntitySubscription
  WHERE SubscriberId = :UserInfo.getUserId() AND ParentId != :UserInfo.getUserId()
  LIMIT 1000];

Set<Id> ids = new Set<Id>();

for(EntitySubscription s : sub){
    ids.add(s.ParentId);
}