The most common way to drive people to your business site is advertising. You cannot succeed without advertising, this is a fact.
You should advertise almost everytime and almost everywhere using a very pleasant, smart and persuasive manner if you want to accomplish your final target: Making Sales
But what to do when clear and noisy advertising is not allowed(e. g discussion lists, discussion forums, etc) or you just send emails with no connection with business?
Should you give up? Should you leave hundreds of members of adiscussion list with no information about your product? No way! You may promote your site with no accusation of unfair behavior using Signature File(s) because, as far as I know, this method of advertising is everywhere accepted without complains.
Here are some hints to improve the task of Signature files:
Be short. When you send emails in HTML format use only one line, the link to your site must be viewed by moving the mouse over this line. When you're in text format use a two lines signature with a classical headline and the link below. At a minimum you should be able to provide is your product/company/site name and URL but ideally you would use and some appropriate words
Be relevant. A post about search engines shouldn't end with a signature file about copywriting.
Use the context. To be truly effective your signature must be as closest as possible to the content of message or topic of forum. For example if you answer postings in a forum to do with any aspect targeted advertising you can provide a signature such as "Get 10,000,000 hits to your website".Let's learn something here. It is not difficult to find 'forbidden' places for blatant advertising, they are everywhere. The biggest problem, and challenge as well, is to be very effective using a very small space.