The solution you linked seems about right but i can’t tell if its scalable and won’t crash on a large scale,
another solution would be to create a non public custom post type with no UI and to act as a “stub” post for each user and keep that post ID in a user meta table, that way you can:
- make easier queries.
- use other post features for users
like: comments,tags,categories,custom taxonomies and all the functionality built for posts. - use post based plugins on a user
profile like: voting, rating, ranking…
and i believe its a much better approach.
take a look at Mike’s answer to a similar question to get you started.