There may be different rules for Americans and Europeans, I think that Russia applies reciprocity logic and applies the same kind of restrictions to country A as country A applies to Russia.
The 90/180 day rule certainly applied to me (European) and was confirmed to me by the Consulate in Luxembourg. Having said this, the longest visa I could apply for was only 90 days in any case.
The important thing for me was that I had to take into account an earlier stay that fell within the 180 day period, which effectively limited the time I could stay on the new visa (i..e less than 90 days).