How do tags help?

[Dason]

This was just going to be a private message to quark but I figured anybody could chip in if they want.

There is the option to add 'tags' to threads to help describe what is contained in them. What does this achieve exactly? I know when searching you can add an option to search only for threads that have a certain tag and when you're looking at a specific subforum you can hover over the tag icon to see what the thread was tagged as. But is there anything else that the tags really achieve? Do these help suggest similar threads? does Google use this information at all?

I partially ask because I was going to make a thread to hopefully start a tagging initiative but then I wondered... what's the point? So I just want to know what the main point of tagging is to see if it's really worth the effort.

[vinux]

In SO the tags are very useful. But here we have sub forums and search. tags may useful when it is less than 4 characters. Because we cannot search 3 letter words in search. Suppose If I am looking something on RGL or some acronym like pca or mle, I cannot search in this forum ( my understanding is TS search take only the 4+ letter words).

Why there is a limit on tags? I found we can add only three.

[quark]

Tags are another way of organizing posts, in addition to forums. For example, somebody has suggested that we create a "Data Visualization" forum, but I was afraid that it would not get enough posts. Tags would work well in this case, and we give a "Data Visualization" tag to appropriate posts. When people click on the tag, it will show all posts with that tag. If there are a lot of posts tagged, we can have the tag cloud on the homepage or at the bottom of all pages, and the most common tags would have a bigger font, which is a nice way of visualizing hot topics. It's like an additional navigation system. Tags also help search engines to properly index the posts.

There is a limit on the number of tags probably because we want the most precise and the best category or summary of the posts. It's similar to the idea of creating posts in the appropriate forum and no cross posting. We want the best tags only.