Directory for Google

1400 ecommerce websites backlinking

[India_max]

I am developing a directory. 1400 customers who have ecommerce websites to be listed on this directory, initially.

They all will have a "Listed/Featured on MyDomain.com" Link on their HomePage.

Now, i am incorporating the following for Google. I humbly request the Google Gurus in here, to guide me, if I am going wrong anywhere. Here's the details:

Since this is a directory for ecommerce/sales websites, all adult, .org, corporate,websites, will not be listed & hence these cats will be absent.

1)Larger number of Main categories & Only 2 Levels Deep Sub Cats. ( As PR Drops, per sub-cat)

2) No .? extentions in URL for the Sub-Cats.

3) For Ad Banners & Google type Text Box Ads on the Right hand (Sykcraper Column), I shall need to have .php extentions.

Do i need any more precautions or features. I really need advice here.

Thanking You in Advance.

regards,

Prash.