Here are examples of a couple of policies in place at other websites.
EXAMPLE 1
We all, well most of us, like to add a signature to our posts as it's one of the few places we can freely mention our businesses etc. However, so as not to distract from the posts by being overly long, signatures are restricted to 4 lines of no more than 65 characters.
Effective immediately, the following restrictions will also apply:
Center and Right align tags are NOT to be used.
The Hr tag is NOT to be used.
The maximum font size permitted is size 3.
EXAMPLE 2
The signature should be composed of the default font only and should be 10 lines maximum(including lines of spaces) when viewed at 1152 x 864. They should conform to the normal Board Rules regarding content. They should not include ascii made images. Colours and links (in accordance with Board Rules) may be used. Any signature seen as being overly long or of an offensive nature etc is liable to be removed without notice.
Forum staff have the final say over what is deemed offensive
Inflammatory Political Statements or Quotes (as Perceived by the Staff) are not permitted in signatures and will be removed.
EXAMPLE 3
A signature is a bit of text (maximum of 255 characters) that you have the option of adding to the end of all your posts. Some people have famous quotes, silly quotes or quotes that have very little meaning to anyone from Earth. You cannot include a picture in your signature.
EXAMPLE 4
The policy of signatures.
quote:
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Unfortunately due to the increased number of multiple line sigs members are creating, which sometimes exceed the length of their posts, we feel that sigs should be restricted to a maximum of 3 lines. This will help make the forums more readable and reduce the amount of scrolling required to read the replys.
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What this means is that any signature you may have, keep it to three lines. If we see a signature that exceeds this three line maximum we may mail you to correct it within a week or we shall step into your profile ourselves and delete your signature. Alternatively, we may just step in and tweak it if it is a simple enough matter to change.
You can check any new signature in your profile by clicking the preview button. It may also be worth reading the Forum FAQ for some of the code and effects you can employ. We have found a common error is over-use of the {centre} tags, resulting in excessive lines of a signature.
Another element to bear in mind is that the restriction to three lines is due to space. So with that in mind signatures that are excessively large due to using the {size} tags will be altered back to something more respectful.