I've observed two subtle but substantial deficiencies in the Ipernity tag system.
First, the tag system doesn't recognize word forms, so you best use singular and plural forms. For example if you are searching for a tag 'zeichnung' you miss docs tagged with 'zeichnungen' unless someone adds both tags.
Second, there seems to be a little bug somewhere that causes or caused some tags (audio files?) to be improperly trimmed.
You'll notice odd tag pairs like 'classica' and 'classical', 'electroni' and 'electronic', 'hous' and 'house' and so on. Probably the bug is now gone because it is seen in audio files uploaded prior to July 11, 2007 (?) However it sometimes interferes with looking for some docs on Ipernity.
Wish - I don't know if this is at all doable but it might be nice to have a feature to help you with searching by tags - if you look for 'flower' to be offered also presentation of docs tagged with equivalent tags in other languages like 'Blume' and 'Fleur'. This way you could have included in your search docs tagged by German/French speaking Ipernity users.