In September 2008, the UniProt/Swiss-Prot group achieved the first complete manual annotation of what is believed to be the full set of human proteins (derived from about 20,000 genes). This was a major milestone as this collection of data is already quite rich in information pertinent to modern biomolecular medical research. But there remains a large gap in our knowledge of human proteins in terms of functional information as well as protein characterization (PTMs, protein/protein interactions, sub cellular locations, etc).