Over the last year, as he has sought to revive the flagging fortunes of Yahoo, CEO and Co-Founder Jerry Yang has ferreted himself away from the spotlight and has seldom made himself available to talk to investors or reporters about what he has been up to.

I dubbed it the “cave” strategy, mostly because that’s what many around Yahoo called it. Since Yang really didn’t have anything good to say about the troubled Internet giant, he didn’t say anything at all.

I always thought that a big mistake, since it was very insular and defensive. Like my politicians, I like my Internet execs able and willing to take on all critics (and for all the grief I have been giving Facebook, in stark contrast to Yahoo, its execs are very willing to go a round with anyone who questions their moves).

So you might have thought that the surprising unsolicited bid to grab Yahoo by Microsoft might have brought out the fighting spirit in Yang.

That’s especially true, since it has been widely reported (and entirely true) that he had rebuffed such advances many times and was actually not shocked (despite what has been reported, Yang had to know it was coming given the weak, stock-depressing quarter he turned in on Tuesday) by the $31 per share offer he received on Thursday.

But, no.

“So they are now deeper in their cave than ever,” reports one frustrated person close to the top execs at Yahoo yesterday, echoing a widespread sentiment at Yahoo’s Sunnyvale, Calif., HQ.

Deeper? Is that even possible? If so, Yang must now be living in the Mariana Trench of the Web world.

But, even if he gets the bends, Yang needs to surface and quickly.

Why? Well, I am no crisis PR expert (Yahoo has hired those–the Abernathy MacGregor Group in New York, in fact).

But, if Yang does want Yahoo to remain independent (which, incredibly at this point, I am told he does) or he wants another alternative (I know there’s backroom blabbing going on, but still) or he just wants to get a better price from Microsoft (he should), he had better get out there and make his case.

He doesn’t have to say what he thinks about the Microsoft incursion specifically, because he needs to wait for the board to respond to that.

But as a potent symbol, Yang could talk up the virtues of Yahoo and its own vision for itself more clearly–something he has had a lot of trouble doing over the last year that has been a factor in landing the company in its current situation.

Microsoft’s CEO Steve Ballmer certainly has been swanning around in front of reporters and investors since he made the Microsoft bid public, carefully laying out his justification for his hostile offer.

That included an interview today with The Wall Street Journal’s Rob Guth, as well as a strategic update he gave to investors for the company, in which he again called the Yahoo bid a “very attractive offer.”

It is simply not, as I have written. Despite Yahoo’s woes, it is easy to make the case that its impressive range of assets and its massive traffic make it a bargain for Microsoft’s effort to make a dent in its fight against Google in the online ad game.

Ballmer said as much today when he noted correctly that “Yahoo can get us farther, sooner.”

And if a workhorse to pull Ballmer to greater glory is what Yang wants to become, then saying nothing is the best way to make that happen.

I am told that Yang is hamstrung from speaking out by lawyers and the once-not-and-now-involved board.

Well, I doubt that is what is keeping the always-cautious Yang from speaking out. It’s just not in his nature to do so, although this might be the time to change that.

Internally, Yang was trying to communicate to his troops and did note in an oddly punctuated all-lower-case internal letter (which I have corrected) to employees on Friday that nothing has been decided yet.

Wrote Yang, along with new frying-pan-into-the-fire Yahoo Non-Executive Chairman Roy Bostock:

“We want to emphasize that absolutely no decisions have been made–and, despite what some people have tried to suggest, there’s certainly no integration process underway. This proposal is just that–a proposal. And it was only made in the last 24 hours. You can be sure the board is going to review it thoughtfully and carefully, and do what’s right for our great company. Microsoft’s proposal is one of many options that we’re evaluating in order to maximize value for our shareholders and employees over the long term. That’s why we will respond to Microsoft after our board has completed a careful review of all of our strategic alternatives.”

Yang went on to urge employees not to let “this situation distract us from our core mission.”

As if.