So what is the logical opposite of using a minus to remove terms? Quotes?

This is what customers remember and do? I highly doubt that.

Or are they trying to reserve the plus now for another feature in the future?

Remember, on Google +, you don't mention @somebody, you mention +somebody. I'm sure they're going to reuse + so you can search for +somebody.

This is stupid on Google's part. People are used to mentioning others via "@" (unless, maybe, Twitter has copyrighted/patented this). Forcing people to use "+" will just make adoption of G+ harder. Google should remember that they're the underdog here, playing catchup to Twitter and FB. Raising the barrier to entry only hurts them.

people have been using @ to mention others since pretty much the beginnings of online discussion, way before facebook and twitter (I'm agreeing with you - this is a stupid move by Google and goes against 15+ years of convention)

Just because something has always been done one way doesnt mean it always has to be done that way.

I think that, while nerds are used to mentioning others via @, regular people are used to putting @ in email addresses. Frankly, I find this change frustrating (for the reason that " is not the opposite of -) but I don't believe regular people are going to have any more difficulty with +Adam than they did with @Adam.

If you type @<name> it gets converted into +<name>.

I agree with the implication of your last question. It would certainly make sense for google to integrate Google Plus directly into their core product. I haven't thought of an exact path this would take, but if you're branding an operator, brand it everywhere.

> but if you're branding an operator, brand it everywhere.

And this behavior is what provoked the statement that the engineers are no longer in control- branding trumping usability.

But, consistency is an important part of usability.

Consistency cuts both ways. There is the branding consistency of the + symbol, and then there is the consistency of how + worked for searches last week vs. this week. My vote is that consistency in usage trumps consistency in branding.

Google+ probably gets much more usage than the + search operator. I'm sad that that part is becoming harder, but if they have a use for + that's integral for a future piece that relates to Google+, the needs of the many and all that.

I just tried Bing, + works on there it seems.

I can't believe it's been almost 10 years of using Google. Default search changed to Bing on all Laptops. I'm done. Fuck Google.

Have you tried DDG? http://duckduckgo.com/about.html

I wonder how ignoring + in all of the millions of existing search links on the internet affects Google's ad revenue...