Hi Sarah - well, I'm not the webmaster (webmistress?

) so I might be talking rubbish here, but I'm pretty certain people here link to their own websites and books, and have their own pictures as avatars (I haven't - I don't really look like this, honest) so I'm sure that's absolutely fine. Why don't you set it up the way you'd like it to be set up, and we can let you know (nicely!) if there seems to be any problem with it? I don't think there
are any rules as such about these kinds of things. Promotion of what one does seems to be welcomed here.
It's welcome in the Promote Your Projects area, not so much elsewhere.
I'm no longer on the committee (so everything I say here is just as a member bringing you up to speed, Sarah, not as an official BFS person setting out firm rules), but when I was we set up a self-promotion forum because promoting your work elsewhere was so fractious, with people unsure of where they stood, and others boiling with fury at any self-promotion. And also because the forums were so dead and we wanted to get people in at any cost.
Interesting that at about the same time similar debates were playing out at Shocklines and Vault of Evil, the former letting it have free rein, and the latter unceremoniously giving it the boot. Of the two the Vault is by far the better read now...
There's no official rule on sigs that I know of, but it would be very unusual to see banners or pictures there, just because they make threads look so boring and repetitive. I wouldn't recommend any big flashing adverts, because people will be sniffy about it, even if they don't tell you. Some members have had their feelings badly hurt over this issue in the past. But as far as text and links in your signature go, more or less any self-promotion is fine.
Avatars - no rule, but it's worth knowing that the use of an artist's work without permission won't go down well with some long-standing members. Not to say people never do it - I had a picture of Jughead as my avatar for a while - but if you're asking what the mores are, it's worth mentioning.
I can't think of much else, except that canvassing for votes is strongly discouraged at awards time.