Well, actually none of these… This is not a merger, but an acquisition… & the last thing Microsoft would want to do is destroy the Yahoo! brand name. The most we will see is: Yahoo! - a Microsoft company.

What to expect?
With a 62% premium on the share price, it would be hard not to see Microsoft taking over Yahoo. The only problem is that will Microsoft be able to sort out the best of Yahoo! or will they merge everything… & end up in a disaster… Google is watching over…

10 years ago, Yahoo! was the dominant search engine, powered by an unknown algorithm called Goggle or Googol (something like that). MSN was nowhere to be seen & Microsoft was releasing Windows 98. Yahoo! was THE COMPANY that owned the web!

10 years later, we are in 2008… & Google is the King of the search engines. It has the most powerful calculator on Earth, is the most updated & around 150 million searches are made every day. Although Yahoo! is playing second to Google, it’s nowhere near to catch-up. Nor will Microsoft, by purchasing Yahoo! The most it will make is gain a 33% market share while Google has twice more at 60%.

What matters is not the search… but the revenue generated from Search Engines! & again Google is years away with its AdSense program. AdSense is the most successful initiative by Google. Anyone can open an AdSense account & start advertising… but most publishers gain only a small percentage (25%?) of the revenue. Everything else goes to Google - it won’t be surprising that AdSense is one of the most profitable businesses in the world.
It’s in the last few years that Microsoft & Yahoo have realised how they’ve completely missed the Search Revenue bandwagon… but they’ll have another try when Microsoft will merge Yahoo Publisher Network with its own AdCenter. It may be late as Google is already thinking further ahead… There are rumours that Google will launch PPP & ReviewMe-like services.

According to Alexa.com, the most visited website in the world is Yahoo.com! Microsoft will hit a major jackpot by owning Yahoo.com, as they will get the more traffic than Google if combined with Live.com & MSN.com… Just hope they will be intelligent enough not to add anything “Live” on the Yahoo! homepage.

Yahoo! Mail is another area that Microsoft will benefit from. Both Yahoo! Mail & Live Mail are among the most popular email services in the world. These two should be kept separate even if Yahoo & Live IDs can be interchanged. Any attempt to mash them up will be disaster! But I will still prefer Gmail for its simplicity & lack of ads.

Yahoo! Messenger should be axed. Windows Live Messenger could benefit from the UI from the Yahoo! team. Nothing more… by making the IDs interchangeable, WLM will work just as perfectly.

Flickr is the most popular photo-sharing network in the world… even better than Picasa Web. What makes Flickr so popular is that its interface is just like most Google services – simple & straight to the point. Microsoft Live services on the other hand are bulky and complicated. Flickr should be untouched.

Yahoo! Widgets… finally something interesting for Microsoft to work on. First thing they’ll do is add sidebar compatibility to all these widgets… or transform Windows Sidebar to support these widgets. In any case, we’ll end up with a wider choice of widgets!

Here’s a comparative (from Long Zheng’s istartedsomething.com) of similar Microsoft & Yahoo! products. Redundant services like Maps, Geocities, Music Jukebox, etc could be removed while merging the best of both worlds.

The future?
Just as Google is intruding into Microsoft territory - Android v/s Windows Mobile, Google OS v/s Windows, Microsoft is strengthening its position on the web. Even then Microsoft will still fall behind Google in other services.
Microsoft Live Spaces cannot compete in any possible way with Blogger… so what can Microsoft do? Acquire Wordpress?
Let's see…