In many open source projects, people are online referred to by their nickname. Talk to them and ask how they want to be called in real life – you’d be surprised how many actually prefer to be called by their first name when you meet in person.
Nicknames in free software communities
About aliases in open source projects
Es gibt ja viele Nicks, die deutlich komplizierter zu sprechen sind als floeff …
Beim persönlichen Treffen geben ja dann auch beide in gleichem Maße etwas von such preis.