Tags, the best way to use?

[TheAdminMarket]

Hello,

I'm wondering which is the best way to work with Tags. It's not vBulletin specific but for all scripts, that's why I'm posting it in this forum.

At least as I know there 2 types for using Tags.

1.- First the user can adds any word he thinks that is more important to work like tag. This has the advantage the freedom of choice, the disadvantage of the big amount of tags. In addition is a common problem when there are typos in the tag.

2.- Admin adds the tags and the user selects one or more from those predefinied tags. The advantage is a compact amount of tags, errors free. Disadvantage that is almost impossible for the admin to add even 70% of the words that a user maybe wants.

Does anyone has experiance on what method other scripts (Forums or CMS like WP, Joomla) etc are using?

Thank you