Video talks on 16S data analysis posted.

URMAP ultra-fast read mapper posted (paper).

~20% of taxonomy annotations in SILVA and Greengenes are wrong (paper).

Taxonomy prediction is <50% accurate for 16S V4 sequences (paper).

97% OTU threshold is wrong for species, should be 99% for full-length 16S, 100% V4 (paper).

OTU accuracy methods

See also
OTU accuracy results
Data, commands and scripts
OTU classification

I used two mock communities (Even and Staggered) of one set of 21 microbial strains created by Haas et al., who created a reference database of 16S sequences in the strains. Reads for these communities were obtained from HMP validation data (454 Titanium) and from a recent paper by Bokulich et al., 2013 (Illumina MiSeq).