Market place ads in your sig or whatever

[WMG]

Is it ok to have a link for a item I have for sale in the market place added to what I think is referred to as the signature line.
Sort of like when every time you post , people myself included have a quote or saying appear at the bottom of their post.
I'd like a link to my for sale ad there also but sometimes places don't want you linking to auctions , etc and wasn't sure and could not find anything on it with a half hearted search.
Why it is or isn't allowed isn't important to me , just a yes or no is all I really need.
Thanks

[xMAC1x]

I've seen it done. I don't know if you spend a night in the box.

[Milsurps]

I've seen it done a lot.

Yup, keep it simple and straight forward. You're GTO.

[WMG]

Thanks to you both.
Nothing wrong with a night in a box , sometimes it's good to get away for awhile