Is there a desirable clip length?

Thanks. You all have given me a lot to think about. I'll try for 15-20 seconds animation clips. Hopefully I can add to my pitiful 4 clips.

Thanks again.

Anita

*edit*

I just looked at my clips on here to see what their times were and they're well under 30 seconds from 10-16 seconds. I probably just don't have enough clips or the right types of clips to get noticed.