My personal opinion is that animated signatures are, uh... a bit too busy.
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The letter of the law is that there are no real public guidelines on animated signatures, except that animated GIFs directly uploaded to the forums for hosting are generally not permitted for most usergroups other than sponsors. Animated GIFs are permitted in certain usergroups for hosting animated avatars and profile images, though. Of course, the software has no way to enforce this on self hosted signature images. There are always other workarounds, too, but anything particularly flashy would end up being subject to moderators discretion.
The spirit of the law is that the goal of the restrictions on signatures is to allow members to see them without having 90% of a page content filled up with flashy images and photos, making it hard to find the few lines of text in between.
You can turn them all off, of course, but I think signatures add a great deal to a community forum, within reason.
Like most things, it ends up being very difficult to police. Sometimes things fly under the radar for weeks until people start reporting it. Then the member takes that as implied consent that it is OK. Other times one is deemed questionable, but we take no action as it isn't quite over the line. Then someone else takes it one step further, justifying it with the presence of the other one. No matter how many rules you create, there is always a loophole or a way to bend them. It's a lot easier for us to stick with "moderator discretion", even though that may vary from day to day and moderator to moderator. For as many people who would get upset because they feel they are being overly scrutinzed when it comes to moderators discretion, just as many would be upset when we try to close the loophole they found in the terms of service or behavior.
Anyway, we do our best. The one you have now looks great, and you're welcome to use this thread as a test! It is kind of a hassle since your signature is updated in all your old posts, too.
Funny story about that and about loopholes. I once included a reference that I was a technician in my signature on a forum at a very popular website where I had been helping answer questions from parents. I was told something about how this certification wasn't accepted or verifiable, so I had to remove it (even though in their defense they actually included the link to the safekids page where you could verify it!). So, I changed it to something informative with a link to Safe Kids USA or SafetyBeltSafe and ultimately my email address. Nope, those were all no-nos, too, under a secret "No Bumper Sticker" rule that appeared in none of the rules or policies they linked for me to defend their stance. Finally, I gained the attention of the head administrator, as they deleted my messages asking for clarification of the secret rules, stating that they do not discuss their public policies in public (?). I suspect this had more to do with the fact that I was answering questions daily and correctly, whereas the moderators would pop in once and a while with marginal responses based on some of their questionable website content (yeah, that never helps your cause!). It was amazing how much of a hassle I got for replying to posts on child seats with short, simple answers. Ultimately, she told me that signatures were not, in fact, allowed at all. Of course, I asked why there was a signature entry field in the profile if this was the case. She [the manager/admin] said she had never noticed it! Nonetheless, I was told to go back into all my old posts and edit out the signatures manually since their software didn't work like this one. Of course, I simply went and bulk deleted all my old posts since that took far less effort. I didn't participate there much after that. They closed that sub forum some time later, as I suspect they knew they lacked the expertise to be any kind of authority on the topic.
Clearly, they didn't appreciate that they had one or more volunteers doing for free what their paid staff was unable to do. We do appreciate that here! Granted, there's no paid staff, but we do try to hassle members as little as possible. Though sometimes it may be hard to believe, we'd rather be doing almost anything else than dealing with signatures and reports and drama and such. We also try to be a little more understanding than the big corporate forums I hope. I also learned that "Moderators discretion" is a lot easier than creating a gazillion rules for every contingency, only to find some wise $@# who finds one that was missed... Sorry to go off on a tangent. It's late and the mind wanders lol.