A couple of things you might want to consider:
- Maintenance of the data.
If the data is going to change often then it would be easier and quicker to have the data normalised so you only have to change it in one place and have all the usages of it automatically update. Conversely, if the data hardly ever changes then this is not a consideration.
- Full text searching.
This should be quicker than doing like '%string%' searches and, depending on your database and what's available, may dictate the format you have store your data in.
In addition there's the obvious thing that storing the text repeatedly in the table(s) will increase the size of your database. This may have an impact on performance or cost you more to make sure you have enough disk space and/or memory available on your server.
Wikipedia has an article on the basics. It's not an area I'm terribly familiar with, just that a colleague is looking into this and there are trade-offs with how the data is organised when doing other searches. Other links - MSDN, MySQL and PostgreSQL
