Using sub-domains - a good idea?

Does using sub-domains help/hinder search engines?

[jetnovo]

Hi there

I'm contemplating using a sub-domain on a site for the first time.

At present the site is www.example.com, but my client has three completely separate divisions in the company (different scale, but similar to the Mitsubishi has Mitsubishi Motors, Mitsubishi Electric, Mitsubishi Foods, etc etc). At the moment these are treated as:

www.example.com/division1
www.example.com/division2
www.example.com/division3

The client wants all three divisions registered separately with search engines. However I would expect search engines would all treat example.com as the same site.

How would search engines respond if I did this:

division1.example.com
division2.example.com
division3.example.com

...? Is it likely to help/hinder my attempts to make a strong differentiation between the three divisions (all of which trade under the same company name)?

Also, I've never used sub-domains before. Do these add any complexity to web builds (I work with flat HTML pages)?

[kazecoder]

Subdomains to my knowledge shouldnt hurt anything. The search engines should treat each subdomain independently as it would a seperate domain. I would think it would help the other divsions since they would be associated with the main domain name and business. IMO.