[R] Strange behavior with poisosn and glm

[Noah Silverman]

Hi,

I'm just learning about poison links for the glm function.

One of the data sets I'm playing with has several of the variables as 
factors (i.e. month, group, etc.)

When I call the glm function with a formula that has a factor variable, 
R automatically converts the variable to a series of variables with 
unique names and binary values.

For example, with this pseudo data:

y        v1        month
2        1            january
3        1.4        februrary
1.5    6.3        february
1.2    4.5        january
5.5    4.0        march

I use this call:

m <- glm(y ~ v1 + month, family="poisson")

R gives me back a model with variables of
Intercept
v1
monthJanuary
monthFebruary
monthMarch

I'm concerned that this might be doing some strange things to my model.  
Can anyone offer some enlightenment?

Thanks!