Hi! I'm designing an art project, which includes a lot of fonts (over 500 names - the original design idea). It's a social kind and not a commercial project. Is this legal? I mean who will ever be able to contact all the 500 authors and ask their permission. Does anybody knows the laws concerning non-commercial social projects? thanks in advance!

The kind of project is irrelevant. The intellectual rights to each of those fonts are owned by some person or organisation, and for those fonts which didn't come with a license granting non-commercial use, you must obtain permission. It is not a good idea to do this in retrospect, for reasons you are now discovering. Not what you want to hear. I'm sorry.

THanks!

And how do you think, if any project with fonts is created only to take a part in design or typography contest. Consider it a personal or a commercial use?

You can find a lot of fonts that are 100% free. You won't need to credit the author, nor pay money. That way you'd avoid a (legal) headache.

Only the author of the font can answere to this question with its personal feeling.

For the rest, +1 with Hanoded : the best for you is to use totaly free fonts.

Thanks a lot! Your thoughts were very helpful!

you may need to give credits to those 500 fonts creators.
or it may hurt their feeling.