zouzas,
On the email campaign, I'm not sure how you would target .us domain name holders or people who have live .us websites (without going through 1 million searches on the whois.us site).
Also the reason I know that advertising is tax deductible for a business is because I advertised for my business last year at
http://www.domainterritory.com and it was tax deductible.
I guess you'd have to determine whether zoned.us is a "business."
I never had really understood how search engines make money, but yahoo obviously makes big money. Yahoo must get the bulk of its money from advertisers who put up ads on yahoo. If you determine that zoned.us is a business under the tax laws, then the advertising would definitely be tax deductible.