a form is a page of input boxes that the visitor can visit and enter in info that can then be sent. For example below is a simple form:
My Simple Form:
Your Name:
favorite color:
You are interested in:
e-mail networks

Opt-in e-mail:
Opt-in e-mail is a Web marketing term for promotional e-mail that recipients have previously requested by signing up at a Web site or special ad banner. Typically, Web users are invited to sign up for promotional information about one or more categories of products or services. Those who sign up have thus "opted in." Anyone sending them e-mail as a result hopes that the message will not be perceived as unwanted

Several companies gather sign-ups at their own site or through specially-designed banner ads and then sell marketers mailing lists of those who have signed up in various interest categories. The marketer sending opt-in e-mail may remind the recipient that they have previously indicated they were interested in receiving such e-mail and that this is NOT spam. The recipient is given an opportunity to be removed from the mailing list if they so choose. The distribution model of sending unsolicited e-mail (spam) and allowing the recipient to request removal is sometimes referred to as "opt-out."

Permission marketing:
Permission marketing is an approach to selling goods and services in which a prospect explicitly agrees in advance to receive marketing information. Opt-in e-mail, where Internet users sign up in advance for information about certain product categories, is a good example of permission marketing. Advocates of permission marketing argue that it is effective because the prospect is more receptive to a message that has been requested in advance and more cost-efficient because the prospect is already identified and targetted. In a world of information overload, automated telemarketing, and spam, most people welcome the idea of permission marketing.
Spam is unsolicited e-mail on the Internet. From the sender's point-of-view, it's a form of bulk mail, often to a list culled from subscribers to a Usenet discussion group or obtained by companies that specialize in creating e-mail distribution lists. To the receiver, it usually seems like junk e-mail. In general, it's not considered good netiquette to send spam. It's generally equivalent to unsolicited phone marketing calls except that the user pays for part of the message since everyone shares the cost of maintaining the Internet.

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