2015 has been a bit of a mediocre year for chip giant Intel (INTC -1.79%). The company expects revenue to be down about 1% for the year and earnings per share to slide as well. This is far from catastrophic, but in a market that seems to prize revenue growth, it's hardly surprising that the stock is down a little over 2% year to date as of this writing.

That being said, despite the ho-hum financial results for the year, the company experienced a number of positive developments that investors -- particularly those with a fairly long-term time horizon -- should keep a close eye on.

Without further ado, here are some of the best Intel headlines in 2015.

Intel launches Xeon D
In early 2015, Intel launched an entirely new family of processors aimed at a number of interesting, high-growth workloads in the data center known as Xeon D. These processors are generally less powerful than the company's workhorse Xeon E5 processors, but they are extremely efficient and integrate a lot of functionality onto the die that the E5 chips don't.

These chips are widely viewed as Intel's answer to (or, perhaps more appropriately, a pre-emptive strike against) solutions from chip vendors looking to build designs around ARM (ARMH) architecture processors for the data center.

Intel acquires Altera
Perhaps the most significant long-term bet that Intel made this year -- and certainly the most interesting headline -- is that the company announced that it planned to acquire programmable logic vendor Altera (NASDAQ: ALTR).

The deal, worth approximately $16.7 billion, is aimed at allowing Intel to do a couple of things. First, the company believes that by migrating Altera's pre-existing product lines to its in-house manufacturing technology, Altera (now known as the "Programmable Solutions Group" within Intel) will be able to gain a leg up on the competition.

More important, though, Intel seems to be most excited about being able to take Altera's FPGA technology and integrating it into its Xeon server processors. If this all works out as Intel hopes, then this could not only strengthen the company's competitive moat in the data center, but should allow it to see increased server chip average selling prices as well due to the integrated FPGA functionality.

3D XPoint announcement
In late July, Intel and memory maker Micron Technology (MU -3.78%) announced a completely new type of memory that they jointly dub 3D XPoint (pronounced "cross point"). Intel claims that this represents the "first new memory category in more than 25 years."

Indeed, the technology isn't meant to replace either traditional NAND flash (which is cheaper than 3D XPoint) or DRAM (which is faster than 3D XPoint), but is instead intended to represent its own "tier" of memory in between the two technologies in a system's memory hierarchy.

This development is significant for Intel in a number of ways. First, the company should see a direct revenue contribution from selling both solid-state drives as well as system memory modules based on the technology. Intel's non-volatile memory business has seen robust revenue growth, although margins in this segment haven't been all that fantastic.

With 3D XPoint -- since it's such a differentiated technology -- Intel should not only see a nice boost in its non-volatile memory revenues as 3D XPoint ramps, but it could also see margin improvement in this area.

Additionally, note that the 3D XPoint memory modules require Intel's upcoming Purley platform in order to work. This benefits Intel in two ways: as a way for Intel to protect its market segment share in servers, as well as incentive for buyers who could make use of this technology to upgrade to the new Intel server chip platform as soon as possible.

An eventful year for Intel
The developments announced in 2015 lay the foundation for the growth that the company aims to achieve in the years ahead. The first Xeon D processors are compelling, but it's the fact that Intel likely has a whole pipeline of successors to Xeon D that's most exciting to me.

The Altera acquisition is another example of this. Altera's current revenue base is nothing to write home about and will only add slightly to Intel's revenue base. However, if Intel is able to successfully integrate Altera's technology with its own, then that could mean that even greater things lie ahead for the company's data center chip business (and, to a lesser extent, its Internet of Things business).

And, finally, the announcement of 3D XPoint is also quite significant. Though the revenue opportunity that Intel may enjoy from the sales of storage and memory devices using 3D XPoint technology, the really interesting thing is that it helps to further protect the company's high margin and fast growing data center business.

As a long-term investor in Intel, I think these headlines are cause to be quite excited for the company's future in the years ahead.