For all I know, barely any open-source Bitcoin software was advertised here in the past, in signatures.
Well, I was pleased to see this initiative:
Non-Profit Forum Signatures Initiative [+ Overview]I am planning to start wearing signatures from there, as long as:
1. They are bitcoin related.
2. The product / project is not a scam (or looks like a scam).
3. I haven't found a good paid campaign that strictly follows bullets (1) and (2).