GeneOntology is a nice project to provide a standard terminology for genes and gene functions, to help avoid the use of synonyms and wrong spelling when describing a gene.
I have been using the GeneOntology for a while, but honestly I think that it contains many errors and that many terms have not enough terms associated. Moreover, the terminology they use is not always clear and there are some duplications.
It is frequent to read in article or in slideshows charts were the GO classification is used to infer the properties of a set of genes... But I wonder if the authors check the GO annotations they use.
What is your experience about GO?