Microsoft's

(MSFT) - Get Report

announcement Friday that it was ending its $400 rebates for PC buyers had investors rubbing their chins about possible impact.

The news floated around the market and came to rest like pixie dust on the shoulders of some stocks.

Rumors started after Friday's close, when the software company announced that it would stop rebates for new subscribers to its

MSN

Internet-access business. Instead, it will offer a free year of MSN to new PC buyers.

The speculation became rife that the pride of Redmond would help its comparatively runty MSN challenge

AOL Time Warner

(AOL)

in a different way, by buying its very own Internet service provider and its subscribers. Sentiment settled on some possible candidates today, including

Juno

(JWEB)

and

NetZero

(NZRO)

. Both shot up after the rumors circulated. Juno was up $1.19, or 64.4%, to $3.03. Net Zero was up 22 cents, or 18.9% to $1.38.

Both Juno and NetZero provide access for free, supported by advertising instead of subscription fees. It's not a model in much favor -- fellow free-access provider

1stUp.com 1

was cut loose from parent

CMGI

(CMGI)

at the end of January.

Higher-priced speculation also favored

EarthLink

(ELNK)

, a fee-based ISP with about 5 million subscribers, roughly the same number as MSN.

EarthLink also rose on the rumor today, closing up 44 cents, or 4.9%, to $9.41.

Jefferies

analyst Fred Moran said he didn't know whether there was any meat to the EarthLink speculation, but said it wasn't a bad idea.

"EarthLink's an attractive acquisition candidate for Microsoft. Given the heavy effort in building a subscriber base, one way to double their

MSN's subscriber base quickly would be to buy it," said Moran. Moran has a hold rating on EarthLink. Jefferies has done underwriting for the company and given it mergers and acquisition advice.

There would be an additional twist to a purchase. EarthLink now has access to AOL Time Warner's cable network, one of the hoops the new media giant agreed to jump through for merger approval from the

Federal Trade Commission

.

Buying EarthLink would give Microsoft a chance to flog its MSN over Time Warner's cable lines even before AOL got on them.