The jargon file defines lossage
lossage /los'*j/ n.
very common The result of a bug or malfunction. This is a mass or collective noun. "What a loss!" and "What lossage!" are nearly synonymous. The former is slightly more particular to the speaker's present circumstances; the latter implies a continuing lose of which the speaker is currently a victim. Thus (for example) a temporary hardware failure is a loss, but bugs in an important tool (like a compiler) are serious lossage.
To me, a posting would have lossage if it was buggy, inaccurate, or suggested stupid or dangerous things (ex. suggesting that -T should be avoided in CGI scripts run as root because of the performance hit caused by tracing all the data movement). Major lossage is that ever so much more so.
You could also take it to mean that the poster was suffering from a bug or other malfunction that caused him/her to post such a post.