> Logically you might think so, but noise is not always noise, sometimes it's what you're interested in reading about, some days it isn't. Spam, however, is always spam.
Spam is not always spam. There is a subset of spam that are obvious spams such as ones that tries to sell you viagra. Outside of that, there are mails that are harder to classify since different people will respond differently to them. It might seem like that's just me being pedantic but the result is that user end up with mail they do not want to receive, and mark it as spam. This is similar to how I respond to news feeds except I dont have an easy "mark as spam" button without blocking that person forever.
G+ should implement some sort of rating system to rank items that I liked and push those ones similar to it higher on the feed.
As I understood it from the context, the point of the quoted comment was that, even for the _same person_, whether something is noise or not varies wildly depending on their state of mind but for spam that is much less true.
Different people might have different opinions about what is and is not spam, but one person will be fairly consistent about it. For example, it doesn't matter much what mood I'm in - I'll almost always classify the same things as spam. But the same cannot be said of classifying things as "interesting" or "not interesting".
Your idea about a preferential ranking system would probably be a good way to go. Definitely better than trying to train a strictly go/no-go filter to recognize "interesting". The way Google+ posts seem to jump around every time I open the page (with no obvious correlation with things like number of comments or +1's), I actually wouldn't be surprised if they are already doing something like that.
Spam is not always spam. There is a subset of spam that are obvious spams such as ones that tries to sell you viagra. Outside of that, there are mails that are harder to classify since different people will respond differently to them. It might seem like that's just me being pedantic but the result is that user end up with mail they do not want to receive, and mark it as spam. This is similar to how I respond to news feeds except I dont have an easy "mark as spam" button without blocking that person forever.
G+ should implement some sort of rating system to rank items that I liked and push those ones similar to it higher on the feed.