Funding to the Source
In order to improve its public image, Yahoo recently organized initiatives like workshops targeted at open source developers. Think of these as the distant equivalent of Googles Summer of Code, which provided funding to Free software projects such as KDE, WordPress, Drupal and various independent projects projects that begin as nothing more than a proposal from an ambitious computer science student with spare time.
Microsoft sells software for the desktop, unlike Yahoo, which is more focused on services that are delivered over the Web. If Microsoft were to acquire Yahoo, there would either be a conflict of interest or a situation where open source projects receive funding if and only if they build upon (even enrich) the Microsoft stack, including Windows. The Yahoo we once knew would no longer offer the same kind of treatment to Free software.
Duplication Makes Convergence
Yahoo and Microsoft offer many similar services and software. There is plenty of overlap. It wouldnt make sense to keep maintaining two competitive products within the same company, so either convergence or deprecation is expected.
Under Microsoft's 'regime', so to speak, Yahoo's software and services are likely to get worse for GNU/Linux users rather than get better. Due to the companies' scale, there are complicated vested interests at play. For starters, think about software compatibility with multiple operating systems.
Let's explore this even further in the sections below.
A Field Guide to Free Software Supporters
Developing a FOSS-based Business
Open Source Pros Pick their Favorite Projects
Open Source OS/2: The Impossible Dream
Open Source Zimbra
Members of the development community of Zimbra, as well as various customers using the software, are rightly worried. Yahoo acquired Zimbra a relatively short while ago and Zimbra competes quite directly against Microsoft Outlook, Exchange, and parts of the "Live"-branded services.
Had Microsoft acquired Yahoo, it is very unlikely that Microsoft would assist businesses that defect away from it by actually fostering Zimbra. Would a plug be pulled?
Zimbra typically runs on a Free software stack with GNU/Linux at the very bottom of this stack. Would Microsoft keep Zimbra and make it more Microsoft stack-oriented? Would it change the project's goals and direction just as it did with Xen after Citrix, arguably a Microsoft ally, had acquired XenSource?
Lights Out for LAMP and FreeBSD?
Yahoo is somewhat popular among BSD advocates because it takes pride in its deployment of FreeBSD-powered servers. Interestingly enough, Hotmail, too, used to run FreeBSD before it was acquired by Microsoft. Hotmail is believed to have been migrated to Microsoft technologies since the takeover, but more recent rumors tend to deny this.
Can Microsoft be using Free software very secretly? Can it actually hide this significant nugget of information from the public eye?
For a definite fact, various Microsoft sites run or depend on GNU/Linux. Networking equipment, including routers at Redmond, has components in it that are built using embedded Linux. And, Microsoft's $6 billion acquisition of aQuantive was a case of buying a company whose infrastructure is based on Free software. The same goes for Newsvine, which Microsoft acquired last year.
So what would be the destiny of Yahoo's own servers? Its difficult to tell, but its possible that a switchover would be inevitable.
Web Browser Support
Yahoo has a history of being relatively Linux-hostile and sometimes hostile toward Web browsers other than Microsoft's Internet Explorer. This is a reputation that Yahoo simply earned for itself. Would this ever be improved were an acquisition by Microsoft materialize? Would things be getting even worse? The latter seems more likely.