I seriously doubt its that high. I've haven't seen cached content on it older than a week or two.
I'll clarify then, yes cached content only lasts a few days but mweb will retrieve articles up to about 230days old. I'm not sure what the exact cut off period is.
I downloaded something recently that was 225 days old.
Uncached downloads are shifted into the p2p grouping so you do get slightly slower speeds but nothing as bad as torrents