Tags are keywords that describe a person's interests, personality type etc. You should only put in one word descriptions and separate each tag by a comma. You can then search for people by Tag so you can find people you share an interest with.
E.g.
Your tags might be as follows:
Cinema, wine, poker, tennis, soccer, outgoing, friendly
Then if someone searches for the tag Tennis you will appear in that search result.
There must be a minimum of 10 people with the same tag for it to appear in the search.