From Wikipedia, the free encyclopedia

For the use of signatures in Wikipedia, see Wikipedia:Sign your posts on talk pages.

The neutrality of this article is disputed. Please see the discussion on the talk page.(December 2007) Please do not remove this message until the dispute is resolved.

A signature block (often abbreviated as signature, sig block, sig file, .sig, dot sig, siggy, or just sig) is a block of text automatically appended at the bottom of an e-mail message, Usenet article, or forum post. This has the effect of "signing off" the message. It is common practice for a signature block to consist of one or more lines containing some brief information on the author of the message. Note that a sig block is not the same as a digital signature. A sig block is easily forged, whereas a digital signature uses cryptographic techniques to provide verifiable proof of authorship.

Information usually contained in a signature block includes the poster's name, phone number and email address, along with other contact details if required, such as URLs for sites owned or favoured by the author. A witty or profound quotation is often included (occasionally automatically generated by such tools as fortune), or an ASCII art picture. Strict rules of capitalization are not followed. Among some groups of people it has been common to include self-classification codes, though the practice is waning.

An email signature is a block of text appended to the end of an email message often containing the sender's name, address, phone number, disclaimer or other contact information. Most email clients, including Microsoft Outlook and Eudora, can be configured to automatically append an email signature with each new message. Most email servers can be configured to append email signatures to all outgoing mail as well.^{[citation needed]}

E-mail signatures are generally recommended to be kept short and sweet. The inclusion of titles such as "MBA" is often considered grandstanding or warlording.

Since by definition these blocks are added automatically to a message, usually regardless of its content, there are guidelines of netiquette regarding their size. The most common guideline, called the McQuary limit, is a size of no more than four lines of less than eighty columns each. This keeps the overall size of the message down, conserving bandwidth as well as the time required to read the message, and ensures that eighty-column terminals (the most common terminal width by far) can display the sig block properly, allowing for programs that reserve the last column for a continuation character; using all eighty columns for text can result in a character wrapping to the next line.

The formatting of the sig block is prescribed somewhat more firmly: it should be displayed as plain text in a fixed-width font (no HTML, images, or other rich text), and must be delimited from the body of the message by a single line consisting of exactly two hyphens, followed by a space, followed by the end of line (i.e., "-- \r\n"). This latter prescription, which goes by many names, including "sig dashes", "signature cut line", and "sig-marker", allows software to automatically mark or remove the sig block as the receiver desires. A correct delimiter is required for a news posting program to receive the Good Netkeeping Seal of Approval.

However, whether due to ignorance or disregard for these guidelines, a great many people use sig blocks that are either formatted improperly or larger than these suggested dimensions. In past decades, such practice was referred to as warlording, named for one particular Usenet regular who openly flouted the guidelines with sig blocks stretching to many hundreds of lines of ASCII art on messages with little or no relevant content.

Many corporations have internal policies requiring outgoing emails to have lengthy "signatures" appended to them, listing dozens of contact methods, disclaiming legal liabilities, notifying of virus scanning methods, and so forth. These corporate signatures are almost universally large (often larger than the message itself), and composed without regard for the netiquette guidelines described above; they are seen as obnoxious and irritating by many who receive them.

Germany may have laws requiring companies to disclose their company name, registration number, place of registration etc. in e-mail signatures^[1]. Ireland's Director of Corporate Enforcement requires all limited companies operating websites to disclose such information in their emails. The UK's ECommerce Regulations^[2] require this information in all emails from limited companies as well.

The use of top-posting (with fullquoting) compounds the problem by causing messages to have ever-lengthening tails of garbage hanging off their end, as various corporate disclaimers, ads from free mail services, mailing list footers, and the like get added.

On web forums, the rules are often less strict on how a signature block is formatted, as Web browsers typically are not operated within the same constraints as text interface applications. Users will typically use a "signature" text area in their given profile for input, which can then allow a user to turn off signatures. Depending on the board's capabilities, signatures may range from a simple line or two of text to an elaborately-constructed HTML piece. Images are often allowed as well, including dynamically updated images (standard size 300x100pixels), usually hosted remotely and modified by a server-side script. The standard restriction for an image signature is around 300 pixels in height, and any width, as long as it does not stretch the forum table.

Signatures are seen as an art form by many of their creators, and there are many websites centered around their creation and display. Most of these websites have competitions, battles and a signature of the week contest, where members submit their entries to have them featured on the main page.

With FidoNet, echomail and netmail software would often add an origin line at the end of a message. This would indicate the FidoNet address and name of the originating system (not the user). The user posting the message would generally not have any control over the origin line. However, single-line taglines, added under user control, would often contain a humorous or witty saying. Multi-line user signature blocks were rare.

However, a tearline standard for FidoNet was included in FTS-0004^[3] and clarified in FSC-0068^[4] as three dashes optionally followed by a space optionally followed by text.

1. ^ "German bureaucracy, coming to your email now"
2. ^ "ECommerce Regulations"
3. ^ "FidoNet EchoMail Specification"
4. ^ "A Proposed Replacement For FTS-0004"

• RFC 1855, "Netiquette Guidelines" (section 2.1.1 contains guidelines on mail)
• RFC 3676, (4.3 Usenet Signature Convention)
• What are the restrictions for a proper signature?
• Tech-Gfx.net is A proper example of what Signature and Signature websites should look like
• Information Release from Ireland's ODCE (pdf)
• How to Create Email Signature in Microsoft Outlook
• Using email signatures in every day business