Both IBM and Sun have moved to a largely open source product portfolio, and both are not reliant on anything Microsoft or Intel have to offer. IBM and Sun also have their own processor technologies (SPARC and PowerPC) and operating systems (AIX and Solaris). While IBM is the world's largest server maker with a share of 31.4%, Sun is fourth with a share of 10.6%.
If IBM were to indeed buy Sun, it would be for an amount of round and about USD 6.5 billion, which would be a 100% premium over Sun's current stock price. IBM could use a boost as companies like HP have made large inroads into the market during the past few years with standardised servers as opposed to the more traditional mainframe approach employed by IBM.
Sun has also approached HP for a possible acquisition, but HP declined the offer. Remember, though, that this is not official news, as it comes form the omnipresent "people familiar with the matter". However, the source is the Wall Street Journal, which is no small fish. Time will tell.
For us enthusiasts there are also concerns. If IBM were to indeed buy Sun, how much sense would it make for IBM to continue spending money on the development of the SPARC architecture? How much sense would it make to pump money into both Solaris and AIX?