SAN FRANCISCO (MarketWatch) -- Microsoft Corp. and Yahoo Inc. have partnered in the past to gain ground on Google Inc., but Internet experts say a possible $50 billion deal to combine the two companies may not be enough to halt Google Inc.

Reports surfaced Friday that Microsoft may try to buy Yahoo.

According to analysts interviewed Friday, a Yahoo YHOO and Microsoft MSFT, -1.04% tandem still fails to significantly dent Google in a key area: Internet search, which has emerged as the most popular way of navigating the Web and the focus of a dominant share of online advertising spending.

Meanwhile, the merger won't address Google's superior technology for determining the most relevant Web pages and search results. Both Yahoo and Microsoft's ad-serving technologies simply don't measure up, say analysts.

"Here are two companies that are having difficulties at the same thing," said Scott Kessler of Standard & Poor's. "With a merger, you get one company still having difficulties at doing that same thing."

Yet, Microsoft may be one of the few companies capable of fixing Yahoo's technology challenges, according to Deutsche Bank analyst Jeetil Patel.

"Even in the best of times, mergers are hard; and this is very dynamic and competitive space," said Forrester analyst Charlene Li. "If one of the main reasons here is to fight and chase Google, I don't think it'll succeed."

There are upsides, to be sure.

The new company would have the world's largest Internet audience, thus giving it a greater chance of winning the kind of blockbuster Internet advertising and search deals usually swinging Google's way.

A Yahoo-Microsoft combination would account for 38% of all U.S. Internet searches, and raises Yahoo's share of Internet search advertising to about 28% worldwide, according to various estimates.

But even with the combination, Google's share of Internet search queries dominates, estimated at 60% in the U.S. and 70% worldwide.

Meanwhile, Microsoft's Internet portal business needs to be re-energized, suffering from an eroding Internet search share, and it's "underperforming" Internet ad-serving business, Citigroup analyst Mark Mahaney said, in a note to clients.

Rather than an acquisition, Yahoo and Microsoft could partner and be just as strong a foil to Google, a number of Internet experts suggested Friday.

Susquehanna Financial analyst Marianne Wolk says there's a 50/50 chance of a Yahoo/Microsoft merger vs. a significant joint venture or business relationship.

Deutsche Bank analyst Jeetil Patel longs for a return to the kind of advertising deal Yahoo and Microsoft once had in place.

Under that relationship, Microsoft was using Yahoo to distribute ads alongside its search engine results and affiliated Web sites. But that partnership has since dissolved, in favor of Microsoft building its own system and Yahoo upgrading its own.

"Making companies bigger doesn't necessarily make them better," said Scott Kessler, an Internet software and services analyst with Standard & Poor's Equity Research.