Industry experts say AOL is a critical swing factor on search technology traffic among the three big Internet media companies--Google, Microsoft and Yahoo--as it once was on online advertising, a category it practically invented in the early 1990s.
Microsoft and Google have each submitted proposals to AOL over the past few weeks.
Google is still very much in the running, the sources said, contradicting Tuesday's Wall Street Journal report that said signs pointed to a deal with Microsoft.
At least one more round of discussions is planned with each of the two parties, one source familiar with the plans said.
An agreement, which now appears unlikely to include selling an equity stake in AOL, is likely to materialize in coming weeks, probably before Christmas, the source said.
The discussions are occurring amid public threats by billionaire investor Carl Icahn, who said last week he would hold Time Warner board members "personally responsible" if they strike a deal that undervalues AOL.
Icahn and a consortium of investment firms have accumulated nearly 3 percent of Time Warner's outstanding shares and have initiated a proxy battle to replace a majority of the Time Warner board.
In other talks, Comcast Corp., which sources said was considering a joint deal with Google, is now also seeking a separate arrangement with AOL, regardless of the outcome. The top U.S. cable operator is discussing how it can market its high-speed Internet service to AOL's, among other topics.
"We're talking to different people about different things," Richard Parsons, chief executive of Time Warner told business leaders at Town Hall Los Angeles on Tuesday. "Everyone brings something different to the party."
AOL made surfing the Internet and chatting online a household phenomenon. But it has been a drag on Time Warner's stock as it hassince the merger of America Online and Time Warner in 2001.
Since then, the Dulles, Va.-based unit has focused on providing free programming and services to boost online advertising revenue.
Google has generated about 11 percent of its revenue in the first half of this year from its current dealto provide search technology to AOL, but this figure overestimates the importance of the deal to the company.
Analysts estimate the net effect of the AOL's business to Google to be between 2 percent and 4 percent of Google revenue.
Analyst Scott Devitt of Stifel Nicolaus said developments across the Internet landscape point to Google rivals seeking to reduce their reliance on Google by building or partnering in Google strongholds like Web search or advertising.
Examples include Microsoft developing its own search technology to News Corp. and Barry Diller's IAC/InterActiveCorp acquiring further online assets.
"We believe there are strong incentives across all of traditional media as well as all of Google's Internet competitors to reduce reliance on Google," Devitt said.
That sentiment is not lost on Microsoft, which is testing a syndicated search system that competes with Google in France and Singapore and plans a worldwide launch next year.
Microsoft's current proposals with AOL involve a simpler deal that would marshal the advertising forces of both companies in a joint venture, one source said.
Time Warner, Microsoft, Comcast and Google declined to comment.