Can we have ads in our signatures?

No. The following is from the forum rules. Note the last line. That includes your signature which is a portion of your profile.

ADVERTISING: A post that attempts to bring public attention to the offering of goods, a product, a business, or a service. The definition remains the same for a non-profit organization, an individual, a charity, a church, etc. This obviously applies to links, banners, or information included in a member's profile that may accomplish the same thing. This also includes the offering of a free product or service as an enticement or lure with an obvious end purpose of selling goods or services. PROHIBITED ON CHRISTIANS UNITE DISCUSSION FORUMS!

SPAM: Generally, this is unsolicited junk mail that may involve everything from advertising to illegal get-rich-quick schemes. Many of them also involve fraud, con games, and other illegal acts. Most generally, this would be the type of mail that you would trash if you received it by regular mail or block if it was received by email. PROHIBITED ON CHRISTIANS UNITE DISCUSSION FORUMS!

SOLICITING: Generally, this is the asking for donations, the offering of business opportunities, and any number of other requests that may be related to spam and/or advertising. This obviously applies to links, banners, or information included in a member's profile that may accomplish the same thing. PROHIBITED ON CHRISTIANS UNITE DISCUSSION FORUMS!

Those who advertise, spam, or solicit on Christians Unite Discussion Forums are wasting their time completely. The posts will be deleted immediately and the user will be warned and/or banned. Prohibited material includes LINKS and anything else that is visible in the post, or profile.