blog design issue...

I know you are all probably thinking "What does this have to do with  
PHP?" and in reality... It's probably stretching it a little bit...  
BUT I am in the process of writing a blog software (Yes I'm aware of  
all the open source, and paid stuff out there... I'm doing this to  
learn :)) I am looking at adding "categories" to my blog posts so I  
can organize my drivel into something that looks somewhat  
professional, or at the very least, organized so you can filter out  
all the crap...

What I'm wondering about though, is would it be better from a database  
design stand point to do a database field for "categories" and then in  
there put "Personal", "Business", "Crap I found funny"  Basically 1  
database field for all the categories I decide to use. OR should I go  
the other route and do 1 database field for each category?

This is going to be a small blog to start, but I guess I should always  
be looking at performance, security, & maintainability right?

I did read the post that tedd put up about looking at storing  
variables differently and am considering going that route... But just  
wanted to know what you all think :)

Oh.... I'm also not expecting to have more then 4 or 5 categories at  
the most.... Unless I release the blog to the public and take  
wordpress down :P

So any help would be greatly appreciated :)

Thanks yall!

Jason Pruim